Opps, one too many letters in an already silly acronym, which I forgot you missed since it came from my Sirius smut fic.

ROTFLMyArseFlexingMusclesOff or Jenn does ROTFLMFexingArseMusclesOff. Either way it's something neither of us seem to be willing to drop because squeezing arse muscles as they flex during the act is quite yummy. :P