For the record, I'm not a member of the Strato-Shitters club. Thank you,... thank you very much.Your flight suit is sealed up tighter than a drum with no integrated neck seal? PHEW! So that particular David Clark suit must have been "Huggy's Forever".
The neck seal was a mod the Shuttle crews did to the suit. We actually do have a face seal, so that the face area gets 100% O2, and the rest of the suit is ambient. You "don't smell shit" until you open up the visor in the chocks. By then, the cockpit is ripe.