Lately when ive been giving my gf oral and fingering her, sometimes ill slip my pussy juiced up finger into her ass a bit, usually just to the 2nd knuckle. At first when I started doing it she was complaining it hurt a little, but now its a little easier and im not entirely sure if she enjoys it, I mean she doesnt say no, doesnt say it hurts all the time and doesnt move around to try to "get it out". But like I said before, its all just juiced no real lube, so maybe it worth it to try that. Shes a pretty small girl, and shes pretty tight as is. I havent really done the finger in the ass during sex though, just kinda rubbed it a little. Do girls go for this kinda stuff normally?