Well, this isn't dirty, per se, but my fave slashy line in all the musical:
"Lord let me find him, that I may see him..."
Because there's this nice pause before he says "safe behind bars", and it just makes me awww. Snookums is in wuv!
Oh, and also: "He knows his way in the dark." Reeeeeally. *suggestive eyebrow waggle*