how?!!

she's probably either really cold or really horny.

I'm curious as to why you want to know? Are you trying to maintain erect nipples? (it may sound like I'm being rude here, but I'm honestly curious)

My nipples are usually erect too and it's a pain in the ass. I don't want to wear a bra with 1000 layers of padding but I also don't want to draw attention to my boobs. :/

p.s. I'm neither particularly cold nor particularly horny during most of the times when my nipples are erect.

I thought I was the only one who noticed. She either needs to put scotch tape over those bad boys or start wearing padded bras.

i usually have hard nipples. i'm going to start using pasties or whatever they're called, those nipple sticker things.
i've never noticed her nips