double relief

When you've been busting to take a dump and a piss, and you get on the toilet to let it all go. The feeling of massive relief is thoroughly liberating.

Jackie: I drank too much at Taco Bell last night and feel horrible
Kelly: A double relief is in order! Off to the ladies' room!

Jeff: You're in a good mood this morning
Tom: I just did a run to the toilet and gave myself a double relief!