When one is taking a standing dump and the shit doesnt snap yet enters the water and to your surprise the heads, which is flat like a cobra from the intsense squeezeing of ones buttcheeks, final resting place is on the toilet seat staring into your soul like a brown cobra.
A mexican shedding cobra is when your having sex and the hole the penis is inside of is too dry, which makes the top layer of skin peel off of the penis.
"How was last night with that new baddy?"
"It was going great for me until I aquired a mexican sheddingcobra."