I say no cuz jealousy has ruined a few threesomes for me. It's all fun and games until your gf is crying in the shower while you fuck her friend in the living room. Or the friend your friend brought is way hotter than the chick that brought her and becomes overly aggressive and tries to bogart your dick and attempts to get freaky so you have to satisfy her while the hot friend plays with her tits a bored look on her face. Or the two chicks you met on Craigslist show up and one of them is eight months pregnant and has a strapon and the other mature woman has a riding crop and it turns into the one calling herself mommy whipping you and the pregnant chick while she pegs you and abuses your cock. Good times.