Tandem Charge

Requirements - As one

During an ally's turn, if they make a charge attack, you can spend an immediate action to charge along with them and make a simple attack. You must charge attack the same creature they attack

Your speed is zero on your next turn.

Turn based games make movement awkward, but the idea is you are moving together, so other positional effects, such as escape route or shield actions, can treat moving allies as within reach for the duration of the movement in circumstances where allies converge on a location or start in positions that are close to each other.