My first kitten did this weird thing where he would lean back, stretching out his paws all the way and just drape himself backwards, either on my lap or in my arms. Totally exposed belly, which yes, actually, he DID want pet. He grew to be super huge too (around 25lbs!) so he would be SUPER imbalanced when doing it in my arms, but he still wouldn't stop doing it, even at risk of falling. He was just a stretchy boi in general since he would also drape himself over my shoulder. Loved that weirdo.