Psychological Explanation Needed

When super-junior kitten Cyrrie pats semi-senior cat Petunnia on the butt, is it because:

1. he's abysmally stupid;
2. he's incurably insane;
3. he's hopelessly suicidal;
4. he's a ... kitten*!

*Inexplicable, incomprehensible, also male, macho, etc.!!!