In the beginning portion of this scene, the bottom is almost in a frenzy, like he's had too much coffee or something. He can't stop running his hands all over the top. When he sucks his cock, he can't do it fast enough.
Once they start fucking, the top really gets into the jackrabbiting for a while. Now he's sort of caught up in the frenzy, like this is a race, and he has to cum first.
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