Simple answer. Yes if the woman keeps her legs closed and/or isn’t remotely attracted to the man keeping him as a backup in plan and doesn’t enjoy extra attention. And yes if the man isn’t remotely attracted to the woman in any way. If either of these things are iffy then it’s an absolute no. So in most cases it’s a no
I guess they can but if I were to have a girlfriend already why would I need a woman friend at all. My woman should be able to do it all for me. If I need advice for the woman/women I’m dealing with I’d just ask my mother/sister or female cousin.