The Blade Mastery feat says this:
You master the shortsword, longsword, scimitar, rapier, and greatsword. You gain the following benefits when using any of them:
- You gain a +1 bonus to attack rolls you make with the weapon.
- On your turn, you can use your reaction to assume a parrying stance, provided you have the weapon in hand. Doing so grants you a +1 bonus to your AC until the start of your next turn or until you’re not holding the weapon.
- When you make an opportunity attack with the weapon, you have advantage on the attack roll.
Its second feature says that using your reaction, you can get a +1 bonus to AC. This lasts until you're not holding your weapon. Does this mean that in multiple consecutive rounds you can use your reaction to get a +1 bonus as long as you're holding the weapon, which could (theoretically) allow you to have, for example, +6 to AC after a minute like this? Or can the bonus only apply once, RAW?