Blech.

You're not overreacting. He's not 15, he's 22. I'd expect more mature attitudes towards sex from a 22 year old. That's some juvenile shit. Yes, I'm 47, but I remember being young super well, and the only time I remember hearing crap like that was from little boys. Grown men don't refer to their partner's genitals in such a weird, derogatory way.

Your BF has some serious growing up to do. This isn't how adults act. Sex is supposed to be, you know, sexy, for both parties. The terms you attribute to him aren't sexy at all. Reminds me of my BF when I was 18 who wanted to suck on my nipples and say "Waah. I'm a baby, num num" as though that was supposed to endear me to him in some way. It's not cute, it's just gross.