it’s a reference to the original MLP Mentally Advanced Series parody of Call of The Cutie. Cheerilee was giving a lecture on their illustrious God leader Celestia and her history wiping out the Gryphon nation. Then Diamond passed her a note to give to Silver and Cheerilee accused her of eating paper again. Diamond’s response was “meep meep” and translated I think into “Nice going mudpony.” or something like that. It’s been a LONG time since the C.A.D. from Hasbro caused series to be rebooted.