Sex and boobs?

This is probably going to sound stupid, but I'm a ftm and everything makes me curious. My nipples are starting to get very moist- just the nipple and I feel it on my bra. I think they're starting to produce already. I'm only 33+5 so I'm not positive... Anyway, is it still "safe" for my hubby to play w my breasts during sex? I've heard breast stimulation, especially once producing colostrum, can cause labor but I have no gage on how true that is!