Yeah, I made that mistake with an ex girlfriend's cat a rather long time back now. It was the cutest, friendliest little cat you have ever met. Would purr against you and go all slitty eyed in ecstacy if you paid attention and petted her. Then she would relax and roll over and present her belly to be rubbed. Which I did, naively, not knowing the routine. It was a trap. The whole damn performance. To shorten the story, the mistake cost me blood. Invitations be damned, never even think about touching an offered cat belly. About a nanosecond or so after the first finger touched the belly, all claws and teeth were instantly buried in my arm. Rather tricky to remove, it turned out. I only, honorary stoner status notwithstanding, never made that mistake again.