I have no problem sharing my bed with anyone of either gender (I'm bisexual, but that's beside the point as long as it's non-sexual sharing of the bed)
I'm actually more surprised that your mom was worried about you sharing with a guy, but not with a girl. I'd think a parent with a straight child be more worried about that type of thing instead of the possibility of (ewwwww) having contact with someone of the same sex. Whatever happened to "boys in one room, girls in another. After lights-out there's no going into the other room"? I mean, that's kind of uptight in itself but it makes sense.
I love to talk about sex and sexuality. It's such a deep and complex topic and most people have very strong opinions about it. It's always interesting to discuss.
People who are uptight about sex and sexuality are lying to themselves about the nature of it. It's not something that should be taboo, and it definitely shouldn't be something where you're told how to understand it. It's something that everyone needs to explore and figure out for themselves. I tend not to talk to uptight people about sex, because chances are they're going to be condescending to people like myself who are open-minded about it. And since they're probably unwilling to change their opinion, there's no point in trying to educate them.