When did I become a napkin?

At dinner tonight, I was sitting with my boys eating some spaghetti and meatballs, talking about Mine Craft when:
Adam:  Mommy! Mommy!

Me:  What Adam?

The child proceeds to wipe his mouth and hands on my white tee shirt.  (Mind you I do not usually wear white for the specific reason I am a klutz and my children think I am their personal napkin.)  He starts giggling hysterically.

Me:  Why did you do that?

Adam:  Because your a napkin.

Me:  No I'm not!  (At this point all three of them are giggling.)

Adam:  Yes.  You are wearing white.

Me:  That does not make me a napkin!!!

Zach:  Well, you are wearing white and napkins are white.

Me:  NO!!!! That does not make me a napkin!

All three:  Yes, yes it does. 

I am so out numbered!  Apparently motherhood and wearing white will make me a personal napkin for my little darlings.