Trying to create a card that guarantees a coin flip while also not making it "broken", is it possible?

Title says it all, here's what i came up with:

Pokemon: happiny
30 hp
Ability: lucky toss
On your next turn, your first coin flip is head. You can't activate this ability 2 turns consecutively.
Attack: some shit that deal 10 damage

Glaring weakenesses:
-The guaranteed coin flip happens in your next turn, not in the same one you activate the ability. This gives the opponent the possibility to prepare himself for whatever you are setting up.
-You can't use the ability each turn (that's what i mean for "consecutively"), so no cheese with dugtrio or similar mons
-Dude has 30 hp, you can kill him pretty quickly with anything that deals damage to the bench

So, what you think? Still to broken? Somewhat balanced, or even too weak?