She said she had never cum from oral before. You thought you could prove her wrong so she bet you that you couldn't do it, and would be locked in chastity until you made it happen. Perhaps you were too confidant in your abilities. You thought you would
You knew they were also locked when they asked to lock you up, but you had no idea they expected you to match the time they already had in their belt, and since she was Ace it wasn't difficult at all for her to last the 3 years she already had.