Yup- that happens to me at times. More often that not, from fingers on my cl_t (mine or my partner's). But usually, after a few minutes of me focusing on him/her, then I am ready to go again.
However, one guy I was with did push me through that point, and after I'd come, he didn't let me rest... just kept going. With a lot of lube, and after he pushed through my protests, I came again. But I mast say, it wasn't *as* pleasurable as the first one, or those when I wait a little for me to "calm down" after one O.
So I think a range of reactions are totally normal!
Luv,
J.