Slaking

Pokemon GO doesn’t have abilities, so it uses a different method to keep Slaking’s huge stats in check: Yawn. Yawn is mechanically similar to - and actually worse than - Splash, as it generates energy slower. Thus, Slaking is reliant solely on its charge moves to deal damage. This is insufficient on offense. Slaking would be better served having Struggle.

On defense, Slaking can scare off casual players with its gargantuan CP, but its bulk is merely above average, and most of the time it’s only doing 1 damage. Its goal is to nail a complacent player with a Play Rough or two.

Best PvE Offensive Moveset

• Yawn, it’s getting late. Which move is Slaking’s best (and only) fast move again?
• Play Rough is clearly superior to all of Slaking’s other charge moves by virtue of it being a 2-bar charge move rather than 1; allowing Slaking to actually put work in.
• Hyper Beam is better than Earthquake, once you get the energy built up to actually use them, of course.
• Hyper Beam is also better than Body Slam, though typical notes about energy loss are relevant here.
• None of these moves are viable, due to Slaking's non-damaging fast move.

Best PvE Defensive Moveset

• Play Rough is superior to Slaking’s other charge moves due to being a multi-bar charge move with an early damage window and excellent counter coverage. Slaking really needs Play Rough in order to have any teeth.
• Body Slam is another three-bar charge move. It receives STAB, but the potential Super Effective bonus from Play Rough means its usually better.
• Hyper Beam offers a unique advantage in that if it isn’t dodged, the majority of Slaking’s counters will be KOed.
• Earthquake is underwhelming in every aspect.  

*Yawn* Try using something with more consistent damage output. Like Shuckle.