Saddlebacking.
Saddlebacking: sad•dle•back•ing \ˈsa-dəl-ˈba-kiŋ\ vb [fr. Saddleback Church] (2009): the phenomenon of Christian teens engaging in unprotected anal sex in order to preserve their virginities.

After attending the Purity Ball, Heather and Bill saddlebacked all night because she’s saving herself for marriage. Unfortunately her parents found out because they got santorum all over the sheets.

(Credit goes to Dan Savage)
( The Resident Loon Not a demographic. Do not measure., Mon 23 Feb 2009, 16:22, 7 replies)

surely
the verb is saddleback i.e. with no 'ing'

\pedants
( djtrialprice, Mon 23 Feb 2009, 17:46, closed)

Alternately
Surely making a gerund of the verb turns it into a noun.
( flake has nothing against your right leg, Mon 23 Feb 2009, 23:12, closed)

then shouldn't it be
Heather and Bill saddlebackinged all night

?
( djtrialprice, Mon 23 Feb 2009, 23:35, closed)

Grammar 101
No, saddleback is the verb. Saddlebacking is the gerund, and therefore a noun. The definition given - "the phenomenon of..." - matches the word, because phenomenon is similarly a noun, but the indicator of the word type - "vb" - does not.

In other words, the OP should look like this:
Saddlebacking: sad•dle•back•ing \ˈsa-dəl-ˈba-kiŋ\ noun [fr. Saddleback Church] (2009): the phenomenon of Christian teens engaging in unprotected anal sex in order to preserve their virginities.

If the definition was for saddleback then it would look something like this:
Saddleback: sad•dle•back \ˈsa-dəl-ˈbak\ vi [fr. Saddleback Church] (2009): to engage in unprotected anal sex in order to preserve one's virginity.
( flake has nothing against your right leg, Tue 24 Feb 2009, 19:29, closed)

The frothy mix
Dan Savage - The best agony uncle in the business, bar none.
( ThisCaledonianClown has left it far too late, Mon 23 Feb 2009, 17:53, closed)

I knew there had to be a good side to abstinence until marriage
And now I've found it. Cheers!
(Helixdaunting, Mon 23 Feb 2009, 22:35, closed)

Yay! and Woo!
Dan Savage rocks. Even here in sunny Hong Kong.

Nice one RL.
(Spreddum O Grrrr. That's my vicious circle, that is., Tue 24 Feb 2009, 5:00, closed)