I was more thinking of the opportunity to learn to play the game from a more conventional stand-point. If the succubus is going to be gone in a few days, as implied earlier, it's a minimal issue and as mentioned, sexy time and combat (unless you're a Klingon) are rare to say the least. If she wants to learn how to play D&D or Pathfinder, the best way to do it isn't as a part-time NPC, but as an actual player with the support of othr players.