Last night, Sinead visited me in bed while I was trying to sleep. I didn't move or make a sound because I appreciated her effort to reach out to me. On the other hand, it was a little painful.
One of the simplest ways to have fun with a cat is to play the "hand under the bedsheet" game. Your hand moves around under the sheet, the cat swats it with with its paws & attacks it with gentle, painless bites. The cat plays at stalking and pouncing, and only rarely does it get out of hand (no pun intended), resulting in a hard chomp or a scratch. Even when that happens, the correct response is (A) not to flinch or scream, because this scares the cat and may cause it to sink its claws in further; and (B) to scold the cat firmly, and forgive it quickly. Cats interpret corporal punishment as playing rough, and hence as permission to play equally rough in return. If you want them to play gentle, you have to be gentle to them.
So I bit my tongue as Sinead sank her claws into my skin in order to balance safely on my feet, and as she nibbled on my toes - once or twice giving them a bite that I really felt, though without breaking skin. This was a rudimentary form of the "hand under the sheet" game, and she obviously hasn't grasped the technique yet. It will come in time. I just hope I still have skin when that time comes.