Cramp.

I'm on my hands and knees, getting fucked. It's going great, even by my exacting standards--I've spent probably the last fifteen minutes riding between plateaus of "this is so good I don't even want to spoil it by coming" and peaks of "wait, yes I do." My friend is fucking me hard and deep and a little rough--earlier in the night we did some really sick nasty play and even though now we're just fucking regular, some of the erotic charge of the play is still with us.

Right now I'm at one of those peaks, or maybe a plateau of peaks. I'm just coming and coming. I'm screaming, moaning, sobbing, making these deep guttural noises that are probably intensely embarassing but I'm miles past caring. I don't even feel the fucking in my pussy anymore-it's my whole body that's getting fucked, his cock setting off decious little explosions way deep in my guts. I just keep coming and it's better than anything.

Then my right calf muscle cramps. Not mildly. It spasms into a rock-hard locked-shut knot and I can't move my leg and it's call-an-ambulance painful. Since I'm already in a mindset of enthusiastically verbalizing sensations, I outright scream in pain. Sex is done for the night. I massage out the lump and take Motrin and go home.

Balls.