Mike,
Don't suck on the tube! Getting MEK up the schnoz, in the mouth and down the lungs ain't the right way to do it. Allow the capillary action to do it for you.
The amount of vapors you're getting in your mouth is probably minimal at best; It would take about 500-5,000 mg/kg of body weight (via oral ingestion) to be considered a lethal dose. Less than that has the potential to make you pretty sick. My concern is that one of these days, you're going to suck for too long, and wind up with a mouthful of MEK--not a pleasant experience. Unfortunately, this type of behavior winds up being a "when" and not an "if"--and you live too far away for me to come visit you in the hospital every day....
A couple of suggestions, brother:
1. Allow enough time for the TNF to pull up enough cement for you to use. Put the TNF in the bottle as you're gathering your thoughts, and getting your processes in order to begin building. In other words, adjust your tasks to compensate for time loss.
2. Go to someplace like Fisher Scientific and buy a rubber pipette bulb. They'll pull up your Tenax without your having to place your mouth on the tube.
3. Ultimately, if filling speed is still an issue, get rid of the TNF and go to a small paint brush to apply your cement. A good 1/0 natural sable round works well...and may be the best way for you to go.
Hope this helps.
Gip