Stripping doesnt work from the start so I need to grind some stats somehow but I dont know what and how.
As far as code goes, Stripping does have lower requirements than the next step, Fondling; as far as actual gameplay goes, however, I have used Stripping only once or twice in 3 [in-game] year-long playthroughs - for me it starts with "a coy smile", at which point NPCs go "nah - maybe one day" (this still increases relationship by 1, bringing the value closer to the required minimum), and somewhere around "warmth in their eyes" Fondling succeeds. After that, throw in a couple 69 antics, and the path to penetrative sex is open. Kissing - the "you can fuck my brains out, but no smooches" of the bunch - I hold out on until they get the "in love" heart icon thingy, just to be sure.
...Or you could just go through all the "need anything" gifting and "compliment personality" flirting stuff.
Also, since gender preferences are a thing, gender of the principal matters - female principal is probably the most difficult playthrough in that regard: having an all-female PTA (poor Carl) is a clear advantage for males, futas have the tools [and reduced chances for balancing purposes] for both genders, and there is always hypnosis/drugs/quests to push the rare cases that resist over the edge.
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