I'm not sure if I'm dumb or it's planned, but I didn't consider the fact that there wouldn't be a reason to get a discount from the formula peddler if I had already bought all of the formulas and selling one doesn't restock it which has locked me out of those events. Also, I can't seem to figure out the masturbation scenes despite ending multiple days with 0 willpower. Maybe it's because I'm playing on story mode? But this has essentially locked me at 25 lewdness which is pretty frustrating because I'll have to start all over again because of a mistake I made fairly early and thought would be reversible.

Maybe a stock refresh could be something to consider changing for a future update? Like, if you sold the sweet memories+ formula to the bookstore, but it wouldn't refresh if you sold it to the drug dealer.

You need to start the day with 0 Willpower to trigger the masturbation scenes. (Just let Womb of Lust build up)
As the development goes on, new lewd scenes are added regularly, so you aren't locked. If you haven't killed the Drug Dealer you can also probably continue getting more Lewdness from his events.