Yeah, you can actually become slave to all the girls you can. Get enslaved by one, then use cheats to remove your collar (I think it was 24, it's been a long time since I last played the game) at least, when I play I remove everything I can (22, 24, 28 and 34 for Vanilla's "equipment"). Then, go get enslaved by someone else. Not sure if you need to remove your collar again (I do it anyway), but repeating the procedure will allow you to become the slave of every girl you want at the same time. I, for example, am a slave to Vanilla and Cherry by the moment (while being their slave, I could get also enslaved by Ronda and Kelly separately, but got rid of them because their fetishes are not my thing). If you lose somehow (for example, get punished by Vanilla), you wake up in the last girl's "bed" you properly slept on (last few days I played I got punished by Vanilla but woke up in Cherry's Room). And Salia, if you ever read this, DON'T BOTHER FIXING IT. It's a great feature to me.
Really? I was going to ask him what happens if he tries to turn on cheats 17 to 19.