A good friend of mine calls it Spend-Kids-Inheritance-ing or SKI-ing. In this situation he is the kid, FIL/MIL are retired. The conversation goes something like this.
Friend: FIL just bought a new camper, like 80 large.
Me: Wow.
Friend: Yeah that MF'r SKI-ing bitch is at it again.
Me: bwahaha
This friend is actually quite mustachian and we talk about MMM all the time, but the SKI-ing FIL/MIL never stops and the joke never gets old!