Nah, gotta go Carpenter on this. She rubs his belly and suddenly his belly turns into a giant mouth which clamps down on her arms. Then dad starts sprouting tentacles and Kurt russel comes in with a flamethrower...
In general, I like the idea of a petite smooth woman and a furry pot-bellied guy getting it on.
Gives me a couple ideas:
1. As she keeps rubbing and watching him get harder, daddy instinctively reaches out and starts caressing daughter while half asleep. She starts to get turned on and suddenly daddy says:
"Hop on up baby girl, time to go for a ride."
Daughter sees he's still mostly out of it and slowly straddles him. Right as dad comes too, she impales herself on him and locks him into a kiss, making his protestations go away.
2. Dad's a were-something. As he gets rubbed, he starts grunting and squealing. In addition to getting aroused, he starts sprouting animal features until he's a humanoid whatever. When he's fully awake, he spies his baby girl and can't recognize her as anyone other than a cute girl whose touching him