Hey mate, the bondage stuff kicks off with Ely on day 3 (spank..) and day 4 (H... glory). As more updates drop, I'll get even more into this (actually, in update 0.65, there'll be police outfits with Rachel).
Thanks. Any questions or suggestions, I'll gladly help you.
(Spoiler: If you want to check out the days I mentioned, after the prologue, on the screen where you pick which companion you want to hang out with in the afternoon, there's a rocket icon. If you click it, it'll send you straight to the end of the update, unlocking the menu for each character's days.)