Parry Master (5e Feat)
From D&D Wiki
Prerequisites: Dexterity of 15 or higher, dual wielding
Immediately after you successfully hit a creature with a dagger, rapier or shortsword, you gain a bonus to your AC equal to your proficiency bonus until the end of your next turn. You also have advantage in opportunity attacks until the end of your next turn. The weapon used to hit must be in your off-hand.