Back in college I thought up the phrase "gay buttsex with men" as a three-element set any two of which implied the third, and...
Back in college I thought up the phrase “gay buttsex with men” as a three-element set any two of which implied the third, and that holds up
You can be gay with men without necessarily implying buttsex is occurring.
“Gay sex with men” implies the butt though, if you carve it that way