Why Earth-Moon-Earth signals are extremely weak, so operators use strict timed sequences: one station transmits during a defined period (commonly one minute or 30 seconds keyed to UTC), then listens while the other transmits. Everyone's clock is synchronized to UTC, which is also what digital EME modes like JT65 and Q65 require in order to decode. That discipline lets weak-signal software integrate an entire transmission period and dig signals out of the noise well below what the ear can hear.
Watch out There are no beacons bouncing off the moon to monitor; EME path timing is predicted from moon rise/set, declination and path loss software, not from lunar beacons. Store-and-forward describes packet or satellite mailbox operation, not EME.
EME = take turns by the clock. Sync to UTC, transmit on your period, listen on theirs.