I think both tags should be nixed, honestly.
Posted under General
The name is fine. If you're suggesting consensual, you're missing the point. Posts like post #363818, post #364652, post #369180, and post #370100 (just to grab a few random) are consensual but not happy sex.
Some people like to see a little cheer. Leave alone.
I don't necessarily think either needs canned, but both should be carefully applied. Those tags should only be used where it is unambiguous (huge happy grin, for example). The alias is a bad idea though, since the meaning of happy_sex is somewhat specialized. An alias to sex would probably be a good idea though. As for a better name, I can't really think of one, consensual really is a different idea than what is meant to be captured.