Tegoshi likes getting into showers with men and apparently enjoys some discreet touching of private parts and naked hugging. He also is used to kissing on the lips once drunk and probably clinging to supposedly familiar men. He clearly enjoys male attention rather than feeling awkward like many would. But I'm sure he would never admit to bisexuality, let alone consider a homosexual relationship.
Then there's Jaejoong who also clings to his friends while drunk, kisses them. And Junsu who likes groping other guys's butts. Of course, these are just the things that got public, I'm sure there's a lot more that we don't know about. At any rate, all of that behaviour is somehow categorized as male bonding and a part of normal heterosexuality.