I heard both of these mondegreens on the radio (a deejay's send-in-your-misconstrued-lyric show)...

Richard Marx (in Hold On to the Night): "Hold on to the mammaries" (should be "memories"!)

Stevie Nicks song (not sure of the title): Should be "You'd better put your kingdom up for sale." Mondegreen: "You'd better put your key down my brassiere."