Slaking's best moveset in Pokémon GO is Yawn and Body Slam, with 10.41 damage per second, and it can deal 391.1 damage before Slaking faints. This is true when battling in neutral weather. You need an Elite Charge TM to get Body Slam.
All Slaking movesets ranked
Here is a complete list of Slaking movesets in Pokémon GO, ranked by their DPS and TDO. You can change the weather and the opposing Pokémon.
|1.||Yawn||Body Slam *||10.41||391.1||25.8|