Toomanystrokes - uncontrollable wriggling and/or bucking sounds like a GOOOOOOOOOD sign to me, but how about a bit of communication between you and her?

Yes she may tell you she's trying to reposition but wouldn't you rather stop than carry on just because YOU like it even though she isn't comfortable any more? And besides if she DOES like it, won't you feel great when she actually tells you that out loud? Good communication = good sex, remember.

Just my two penneth.

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