Like some peeps some cats just don't see tail to tail,maybe it's unrequited kitty love on Tipsys part and he's not having it,unless you can jelous cat proof your garden keep spraying the jelous cat with the water or try and show him that you don't mind him visiting but he has to play nice,sounds like he wants you for himself-but either way it's not good for tipsy being jumped on on her own turf-maybe he's a she and because she knows tipsy's spayed doesn't see what use she is(assuming she/he is entire)-entires do pick on spays or neuters as they see them as useless and inferior-or could be simple jealousy,maybe when he's naughty to tipsy-you ignore him and when he's good reward him with a tiny treat and cuddle
