It's because they smell like you. Though maybe you should learn to pick them up. My dogs use to do that. But I suppose if she's not destroying them you're fine. She'll probably grow out of it too.

wash them after because that sounds adorable

She is obviously comforted by your scent. Wear a tshirt to bed every night for a week and then give it to her to sleep with.

Give her a pair of your unwashed socks or something. she likes the way you smell and wants to fall asleep with you.

In a way, that's actually kind of cute lol

That's adorable, honestly

When I read the first half of the first sentence, I thought it was going to be so much better than it was...

Um be glad she isn't chewing or destroying them! If all she is doing is sleeping with them you are already a few steps ahead of my dog and me!

I have a cat who sometimes starts to cuddle with my bras after I take them off and drop them on the floor. I don't know if he's just attracted to the scent or the warmth, but it would make for an interesting cat video.

Perhaps you should buy her her own pack of undies...