It's very hard to finish for my gf from just penetration, so sometimes she's using a vibrator to help herself during doggy or missionary. I have no problems with that and I start to really concentrate on keeping the same pace to make her finish, but for some reason I keep getting soft and it fucks up everything. I like when she's enjoying herself with a toy, but I just can't enjoy it with her and I don't know why. And when she's putting a toy away everything going smooth again. Maybe someone else had this problem and could help me.