Tsareena learns Play Rough exclusively as an egg move in Gen 7. It's only compatible parent is Comfey, which learns Play Rough as its final level up move at level 49.
Source
However, luckily for you, in Gen 7 the move reminder can teach a Pokemon a move it will learn at a later level. So if you've unlocked the Move Reminder at the Mt. Lanakila Pokemon Center, you can immediately teach your Comfey Play Rough, no matter what level it is.
Then breed Comfey with your female Tsareena or a pre-evolution. The Bounsweet that will hatch out of the egg will have Play Rough.
Sorry for giving wrong information the first time, and thanks Pogokira for reminding me!