I'd have to check through the game code to be sure, but I believe cellulite and stretch marks only appear in the sex scene right now & only for the NPC, not the player. I want to involve these features a lot more in the next big update, which will have lots of naked content where they'll be visible and described, plus naked full body images of the player and girls displaying them.
I'll also add a description of cellulite and stretch marks to the beach scenes, as they should be visible there.
Regarding hose feed mixes, I'll add an option to request a particular mix from a feeder NPC. Because of its power, the concentrate won't be picked by the feeder independently (outside the facility).