lol any tips

So my boyfriend and I were in the mood while in his car we looked for a spot and parked and I was on top we were making out and i was moving like I would when I ride him he usually fingers me laying down but this time he fingered me while on top only this time he also fingered me through my anus at first it felt ok but after several minutes it started to feel like pressure back there it was like a good pressure but yet a little uncomfortable is there any tips to actually enjoy or is it normal to feel uncomfortable