@Sharkexpert12 Thats because when MC hit on her weakness spot (her ass), she got this addiction somehow.
We as humans sometimes has some kind fetishes (believe it or not) that cant be erased even though we try to forget it no matter how long or how hard it is, its still lingering in our body.
Aside from her past, she still remember her mission, but looks like she enjoyed being hit even more than that.