(slang) To perform cunnilingus on or to have coitus with a woman.
I bought her a drink, and she said "Let's go to my place and you can muffdive me all night long."
To descend upon the muff(s) in question in a thermally ascending manner, partaking with great ravishment of the toe belonging to ruminant mammals of the genus Camelus. This will usually cause the aforementhioned muff to quiver most uncontrollably while exuding large amounts of succulent lubricating liquids.
Muffdiving was solely a gentlemans sport until the last century.