Potions are for Hermione. You got them from Snape or find ingredients from dorm, forest, lake, ect. (basically anywhere except the two shop and room of mirror) and use it at a special room(at least it used to be, haven't refound it yet). Use them in the wardrobe, misc. section. The collar i have no idea.
The potions were taken out again for 1.38, but are supposed to return at some point in the future. There are still some reeferences to them in the game, but at present they can't be used. I think the same may apply to the collar, as I too couldn't find any way to use it though I'd successfully done so in an earlier version.
I think it's just because of this graphical update. I think it makes sense to standardize the models before moving forward with the new artist -the art of the last artist they had was pretty jarring when characters drawn by different artists were standing next to eachother, or when a character was animated in a different style than the base model. Besides this update what else has been removed?
Potions are still not there in latest update. Regarding cheating, I would advise to only use money, slytherin points, mood resets and book cheats. Never had any bugs using only those.
It took me forever to get it as well, and I'm not sure what changed, whether it was the new version or something else, but when I did a Titjob (Max Whoring) and had Genie cum on her tits it did it. It's worth noting however that this isn't the first time I did it, so maybe you have to do it several times.
