With me it's pump-pump-pump- SQUIRT! As soon as I feel her tits on my chest I just can't help it. I've never gone longer than a minute.
Also if I thrust in and out longer than a few times and she's moving I slip out constantly, or start to get soft, and she says she hates the "jabbing" feeling of me poking on her cunt lips trying to get it back in. Still, as soon as I put it in she grabs my ass and tells me she's cumming, so it must feel good to her even though it's over in 30 seconds. I do usually lay by her and rub her pussy though afterwards.
I have noticed that when she's with another man her chest and nipples get far more red and flushed, and she seems more excited, but as long as she enjoys what I do to her and cums hard that's OK.