kissociate
Not quite friends, with benefits. A non-exclusive sexual partner of mild familiarity, but with whom an ongoing physical relationship has pre-empted and superceded any other meaningful friendship.
"My kissociate Melvin and I were just boning in the copy room."
"Is that Melvin Flumly from accounting, or Melvin Pilkington, from sales?"
<shrugs> "couldn't tell ya..."
"Is that Melvin Flumly from accounting, or Melvin Pilkington, from sales?"
<shrugs> "couldn't tell ya..."