when women are on the blob (Their monthlies) they get a little cranky and moody. You cant win an arguement with a woman thats on the blob.
Come to think of it, you cant win an arguement with a woman period. Well, you can, but she'll make you pay for it.
Manblob is the male equivilent.
Men may not bleed like the women do for obvious reasons, but they get just as cranky, argumentative and stropy.
Dave:Whats the matter with you?
James: Fuckoff you cancerous polyp on the anus of humanity !!
Dave: Oh you have manblob.
*dave kicks James in the Mangina*