Ok. I’ll start:
M: Giggle Stick.
F: Wizard’s Sleeve
M: Little Elvis
F: Woozle
Mr. Happy and the Boys
:eek: At first I read the thread title as favorite name for pet genitalia.
his : PJ
mine doesn’t have a name.
We call mine “spike” and her’s, “Miss Kitty”. We call her breasts “the kids” and my testicles, “the boys”.
His: The Trinity (because I see more than just God) 
Mine: Mercy, the Monkey (it’s a looooong story – but the alliteration works)
coochie snorcher!
Still not exactly sure if it’s in reference to virginity or vagina but OMG! 
Coochie Snorcher!!
His: John Henry and the twins
Hers: Glorificus (Glory for short)
Makes the old hymn line “Comin’ into glory” mean so much more…
Hers: Piesafe
His: Melvin & the manberries
Mine:
“Single-barrel pump-action yogurt rifle.”
Mine: Leonard (I have no idea why)
Hers: Chachi (I have no idea why)
His: Charlie ( not really sure how that …uh…came about.)
Me: None.
However, when the kids have seen me nekkid and my son asked me " What all that hair, mama?"
I replied, " The Bermuda Triangle, son. The Bermuda Triangle."
When he wants to make me giggle he refers to it as his nib-nub… and mine is a fairy cake… apparantly…
Makes me smirk everytime… especially when he’s after nib-nub wub
M: Furry Mongoose (:))
F: Personality (as in, “Honey, your personality is showing.”)
Guy: Wanger
Girl: Pooter
I call it winky, cause it is non-threatening. I am also a grower not a shower.
I surprise my victims.
They look disappointed at first, then a look of awe comes across their face.
I always used to call mine buttercup but I try to keep it to myself.* The only thing I ever call his is “my cock” but I try to keep that to myself too. It’s just extremely confusing and I’m not here to bewilder. Also, even if he did understand that I don’t wish I had a penis, he still might feel trapped and frightened if I declared ownership.
*the nickname. I’m pretty good about keeping my vagina to myself most of the time too.
I don’t have a pet name for my genitalia, but I used to call my breasts Beaker and Bunsen (I had a cool Muppets shirt). I like the term snapper for a vagina. And my ex used to call his Killer.
John and Mary[these names have stuck from when I was a kid] When the Dustin Hoffman/Mia Farrow movie “John and Mary” came on the scene[as it were], I could only smile quietly to myself.