pal up

verb2

1. •
   To form an alliance.

   • WHEN union-busting coal operators and the sowers of red philosopies "pal" up together it is the beginning of a situation that affects the entire country. — 1928
2. •
   (UK, informal) To become friends.

   • ... you could make a bit of conversation.' 'I don't want to. I'm on holiday with my family. I don't want to pal up with some bloke from the Pru, just because he's asked me to pass the sauce.' — 1996