They're complimenting you. In a lame, roundabout way. They might not even know it, also. Perhaps they are giggling little monkey boys. But it's a definite compliment. When a mother is naturally hot, then usually so is her daughter.
I say naturally, of course. If the mother has had so much Botox it looks like she's been hit in the face with a shovel, then all bets are off.
Your guy friends don't even realize they're actually calling you hot when they're rolling their eyeballs up and down your mother's every curve. Stupid, stupid guy friends.
I'm hoping these guys are just a pack of doofus bros you roll with and not your boyfriend. It's fine for a boyfriend to compliment your mother. But he should be complimenting you instead of the woman who squeezed you out of her gentle love district. It's his job. Much the way it's your job to tell him he's the biggest you've ever had.
He should run a finger across your cheek and boldly say "My heart is solar-powered and I need your face for a charge." His kiss should be inevitable, like thunder after lightening. A man should never be coy. A man tells his woman he thinks she's fine. Later, he might mention her smoking hot mother. But only in passing. And only in a way that actually says "Now I know that you will always be hot. I will stay with you."
To recap: if he thinks your mom is hot, then he thinks you are hot.
hot mom=hot daughter? not necessarily. (see: rumer willis, alexa ray joel)
Meh...if the guy friends are just joking around or something that's one thing, but when it crosses over into stuff like "man, I would so like to do her" that gets a little creepy and kinda offensive. So, yeah, I wouldn't mind my guy telling me how great-looking my mom is but once is enough. I don't need to hear what's he really thinking. *shudders*