Shoesession

Given your results already, there is probably no real need to experiment further as it would seem fairly certain he does not have a boot / shoe fetish, it is your scent he is into, while as the carrier of that scent, he will continue to give his repeated affection to boots and shoes you have worn.
Of course, properly accounting variables and sample size can make a difference to accurate results, so further observations would take current conclusions closer to certainty.
What style shoes would I suggest?
Well, we have not yet seen any of yours to judge Charlies current taste, but there are various different preferences and variations of the fetish. I tend toward everyday styles and classic sexy, so for the right pair of patent cuties, I would perhaps even be prepared to take my turn after Charlie had his. Again personally, there is of course a right time for wellies, for stout walking shoes and boots etc, but in the same way as poo - nowhere near sex, and sorry to others, but for me no crocs, no uggs, no sneakers, no slippers etc. either

Now, how to ask a girl friend or sister if you can borrow and use their shoes in sexual activity, is a question which will have obsessively enagaged and deeply troubled members of this board for much of their adult life, and of course, what you actually want to do, is to ask a girl friend or sister if you can borrow their shoes to engage in sexual activity with your dog..... Not sure I can really be of much help so good luck with that, but if you discover the ideal then please tell.
OK what can I usefully add? not perhaps appropriate for your situation, but for me success has frequently involved a lot of anguish, a lot of alcohol, and tongue; a lot of tongue.....
Hmm, come here Charlie!

Love to buy your boots of u

Hi M.
Finally made a reply to previous, but found things have already moved on with you over the weekend.
Have not seen pictures of any of his playthings, will we get to see them soon?
Many things impede, it takes time to properly word and to find some appropriate and amusing images which are not too lewd.

It seems that getting your hands on - and of course, Charlies c--k into a pair of your sisters was easy. While his positive response to her heels is noted, how high, what size and color, are they worn or almost pristine, are they pumps, sandals or other, and I think him enjoying them offers no firm conclusion. You assume a general attraction to foot odor, which may be true, but as a conclusion ignores the matter of a family relationship meaning there are likely some similarities in the way you both smell, and so his attraction to her shoes could be because in his more olfactory world, you are both similarly stimulating.
Of course, his reaction could still be caused by some entirely different odors.
Do you know about your sisters sex life? Had her shoes received any sexual attention before last weekend or was Charlie their first? Of course, all yours and her footwear may have been secretly enjoying a full and varied sex life without yours or her knowledge or involvement, even one furtive rub may have given them a plethora of interesting sexual scents for a particularly discerning nose to wish to add to.
Further testing and observation will help take current conclusions closer to certainty, and you say you are getting other shoes to try this week, he is a lucky boy.
You may want to consider whether he shows preference to heels, wedges, flats, pumps, sandals, peeps etc. towards bigger shoes which he flops around in, or towards something small which he has to be (get down Shep) squeezed into.
It seems further testing and observation would certainly be beneficial, and of course, you should not ignore experimental repeatability.
I would suggest each style is tested at least three times, and the results of each event carefully considered and interpreted, although of course not undertaken in too rapid succession. You both need recovery time, a good meal or two, some nice walks and likely some ball and other games in between, so yet again, lucky, lucky boy!

Well done for devising an appropriate test method (which as an aside is my most preferred), although I also find that hand movement animating the shoe and perhaps gently squeezing gives the lucky recipient a most explosive and pleasurable experience.
Now, while you previously described only enabling his solo sexual adventures by leaving specific footwear available for him to enjoy, in your last you described becoming actively involved by holding the shoe for him to cum in, and as you are now having a more direct involvement there are various ethical, moral and emotional considerations.

Regarding only immediate matters such as family involvement and age, some members find any hint of incestuous or younger content unacceptable.
Your sister lives somewhere else to you, and In a mature and adult way, you asked to borrow, she selected and then brought you a pair of her heeled shoes, so although not explicitly stated, it is implied that you, she, and the footwear are of an acceptable age to continue these games, but also, how old is Charlie?
Applying some of the ethical concerns members have raised previously on the board, you may wish to consider not using your sisters, not to even imagine or fantasise the fun you and Charlie could have with other family members or any younger shoes whether related or not, just continue to bring him off in your own or others of known provenance which are completely age and relationship acceptable.
Finally, is animal testing ever morally or ethically acceptable?
Charlie is one lucky dog, and while he cannot answer questions himself, you are now close to and seem to be enjoying more intimate action, so will hopefully be able to make some qualitative and perhaps quantitative judgments of how much he really appreciates the various shoes under test.

Living with a shoe fetish is difficult.
Ok, its probably transference, but Is it only me that finds the idea/mental image of Margaret giving Charlie a shoejob kind of interesting/exciting?

MargeretP , simply , your dog has a boot and shoe fetish . Maybe you can try further with mules and wedges and see the results ... But it will probably be the same outCUM , lol . I think Charlie doesnt mind ... at the contrary .

Shoddy90 - lol , youre not the only one ... despite that would be very controversial to some people , it would be also very hot ( maybe belonging to "Gross Stuff" category on the forum ) . Once , curiosity got me and I checked the net for various odd videos ... including one where a woman gave dog a footjob ( it was the only one of a kind ) . I must admit , I am definetly not a zoophile , but that video was something very hot to me - dog squirted so much it hit the woman into an eye , lol . Seems like maybe dogs like it even more than male humans ...

Very sexy , let him have he's way with your shoes . Maybe help him get off

Love to see pictures

MargeretP - definetly try using some heels like this ... the softer the better

My wife will donate pair of her flats , as long as she gets pictures of what he dose to them

Interesting issue.

Hi M,
Apologies, as I see my previous additions to your thread have been quite long, so a quickie this time.

Although Charlie might be so besotted with your smell and so excited by what you are doing to him that he will fully respond to anything you decide to bring him off in, please have some consideration, and make sure all footwear is cute, not dirty, smelly, ugly or deformed.

If any indecision, you are welcome to use the list I made before and repeat here;
no crocs, no uggs, no sneakers, no slippers etc. to which please add "generally no flats", although as in all things related to sex and footwear, never say never.
Finally, I saw this picture on another thread which made me think I should warn you to clean your sisters shoes, as if cum is lefty to dry, particularly if left to build up over a number of sessions, this may happen.
Of course, if you are having fun with them yourself and leave the evidence for all to see, then others could join in and you might never know, unless you find them still wet, like here ....

While seeing these stains are a visually obvious way to find out about your husband, brothers, boyfriends,
sisters boyfriends etc sexual adventures, wipe them out if you do not want her to know.

Now, if your find your shoes show those marks or any other sign of sexual activity unknown to you, and if when you confront your sister/flatmate etc she is highly defensive, then it might be that she is sensitive at having been caught out because they play with them together, or of course, she may just like to play with them all by herself!