It's the curves of his body Tony loves best. The angular jut of his hips. His rippled abdomen. The nape of his neck when it's all salty and sweaty.
Tony loves all of that about Kerry and more.
When he's fucking him and Tony can make him lose control He lives for that.
Some people (Tony knew most of them) thought Kerry was too thin. That he needed to gain weight.
Tony thought Kerry was just right.