All I can say is DAYUM!
Speaking of "flexibility" reminds me of a time my buddy and I were sittin' on the patio shootin' sh$t and downing some suds. Our lab Max was there and proceeded to clean his junk like dogs do. I looked at my buddy and said:
"Bet you wish you could do that"
"Damn right" came his reply.
"Well ... ok", I said, "but I gotta warn you that Max will probably bite the hell out of you if you do"
Yep ... my buddy walked right into that one.
Thanks for the link and letting me re-live a fond memory of past days!