It's the lady or man friend that you keep in the batting line up as a potential future option.
This is that special someone, who you don't really find all that special. They dote on you--it feels great--and you allow them to tag along in your social sphere as a cushion to your ego, and/or potential booty call.
Caution! If you do call on the booty, know that you compromise the bond between you and your Honey in the Hole. The only way it lasts is if your HITH thinks that there is a chance for a relationship. Hurt them, and you will lose the ego cushion and be forced to recon with the world on your own terms.
A: So are you hittin' that Samantha chick or what?
B: No dog. She totally wants to, but I'm holding on to her for a rainy day. She's my Honey in the Hole.
A: That's selfish.
B: Blow me