I usually take my post workout shake right after I finish lifting. Like, I walk up the stairs and drink the shake. Sometimes my stomach feels bad about that. I told my dad that, and he said you should wait 20 minutes after your workout to take the shake becuase when you lift your stomach basically shuts off and has to turn back on again (in laymens terms). Do you guys wait about 20 minutes, or do you just drink it up right away?