STCP-1471-A gives a Skull Charm accessory, and wearing it when you go to sleep triggers her to join you in bed, thus the Cowgirl. If you want an actual restful sleep, then take the charm off.
Ok I didn't actually beat her I just ran away. Thanks!
nevermind, you have to lose to her and then she leaves the charm on the second floor on the ground, for anyone wondering
