scratch one's own itch

From scratch an itch

scratch one's own itch (third-person singular simple present scratches one's own itch, present participle scratching one's own itch, simple past and past participle scratched one's own itch)

1. (idiomatic) To do something out of motivation to solve a personal problem; to take matters into one's own hands.
   • 1999, Eric S. Raymond, The Cathedral and the Bazaar, section 2:

     Every good work of software starts by scratching a developer's personal itch.

   • 2013, The Escape Manifesto: Quit Your Corporate Job. Do Something Different!:

     The best advice for coming up with a business idea is "scratch your own itch". This is good advice for a variety of reasons. If you can think of a problem that you'd like a business to solve for you, the chances are other people share that problem.

2. (idiomatic, euphemistic) to masturbate