Tired of Rainbow Dash's boasting, Twilight casts a spell to make her head swell bigger whenever she tries to brag. The spell, it turns out, does make her head bigger - and the rest of her, too. Now the evergrowing Dash can't see a reason to stop bragging. After all, it feels so good.

[Macro] [Dominance]

Cover art drawn by AlloyRabbit, who makes the most wonderful large ponies.