yep you are soft locked, i started a new save because i randomly drinked it the first time
Probably not true, i emptied my inventory at some point after opening the locker and i got the clue later following the instructions i saw here, so can't be soft locked. I don't think you need to drink whatever it is in a particular place or time. Or maybe i just did it right without knowing, but i find that hard to believe.
EDIT: I just saw the other post. So i actually did it right without knowing. Weird.
BTW, am i retarded or you can just choose between 3 poses? I know at the love hotel you can see a few more, but it seems pretty limited knowing that there are actually more animations you can see at events. Also, i'm pretty sure there's supposed to be sleep sex at some point. Is that a particular event?