I have gone through a long journey. I have been a virgin, barely able to get a kiss from a girl. I studied pick up vigorously, and spent a lot of time learning canned material. I had success, and am continuing to have success, although I have transitioned more into natural game.

I now find myself in the position where I need to protect my success. I am currently having sexual relationships with 4 different girls, all very attractive. They are all pretty casual relationships, we have our fun, but I am worried that a couple of the girls are interested in taking the next step. They are all vaguely aware that I am seeing other girls, but they don't know the extent of it.

How do you guys manage multiple girls at once?
Are there any ways to protect your girls from having someone take them?
What do I say if one of the girls wants to take it to the next level?
How Is it advisable to see even more girls? At what number of girls is it unmanageable?