Fair warning/ hint/ suggestion:
For those who havent seen the wiki pages and for those who'd like their mc to become a bimbo slut in the most lore friendly way:
One simple tip: Get as friendly with a gopnik named nikolai as possible. To find him during morning and afternoon breaks, you'll get the option saying hang out with the gopniks. Go and talk to him as many times as you can. You'll know you're doing stuff correctly when he presents you with a gift, necklace iirc. From there on keep on making dumb choices whenever you can. The whole thing should take about a week and a half, in game time at the most.
This is only for an mc who isn't already a slut. This will also not work if your mc has a bad reputation. You'll miss out on little content with other npcs but unlock a lot more in the form of forced prostitution, willing prostitution, etc.
Have Fun!