Funniest piece of sexual innuendo?

Oh, don't kid yourselves. Frasier may have been the most sophisticated American sitcom of its day, but at times it certainly reveled in ribaldry.

A Season One example, which followed an emotionally intimate conversation with Daphne laying supine in a short nightie:

Daphne: "Dr. Crane! Your glockenspiel has sprung to life."