it means 'very happy'. pigs lack functional sweat glands and are almost incapable of panting. rolling around in the mud helps to keep pigs from overheating when it gets too hot outside.
sushi and sashi enjoyed a mud bath. they saw the mud puddles behind the building and wanted to wallow in them. there was no way i was going to let them do that as those puddles came from the trash bins and must hold a multitude of germs and bacteria and various other sins. so i said i'll melt some chocolate and they can pretend it's mud and they can wallow in it. they liked the idea as they can eat the "mud". i didn't tell them they were the expired chocolate from the beginning of the pandemic. after all they're pigs and pigs eat anything.
in hindsight, i should've used the new chocolates that way i could've had some, too! but i thought it too late when i was already having a hard time giving them a bath.
They definitely look as if they are enjoying their mud bath! I know I would be if I could eat the bath! However, will they get clean from this though? FAV