How can I seem relaxed after monster flops?

[DrewOnTilt]

I think I have a tell. At my low to mid limits the fish probably don't notice, but I'd like to nip it in the bud.

When I flop a good hand - top set, nut straight, etc. - I can feel myself stiffen up like a board, and my heart rate jumps. Last night I flopped the nut straight in a big pot, and I thought that my chest was going to explode. In this case it didn't matter because I was at a table full of fish, but I could feel it nonetheless.

I've tried taking deep breaths, but that doesn't seem to help. I've tried diverting my attention away from the flop, but that seems unnatural and too obvious.

Help?