>No "sex" or "nude" tag
So what is one to do if they want to look at lewds only?

Ah nevermind cripple. I read your post again.
Searching rating:explicit works.
Should there be yuri or threesome tags though? I figure some people might want to search only for that.

I don't believe it necessary, searching for the number of characters as well as rating essentially yields the same result.