I have a tip (if anyone else has any tips please feel free to post!) This has worked for me so far...I hope it can help someone else.
A while back I had a bad cough which triggered my gag reflex and made me feel like I was about to throw up (you know what I mean right)...for some reason I thought to put ice on my head so I ran to the kitchen and got an ice cube and rubbed it across my forehead until the feeling went away. It worked...the cold ice got my mind off of the gag feeling and it went away in a couple minutes and I didn't throw up.
So I tried it with my trich. I had the feeling to pull and went to the fridge and got an ice cube, held it in my fingers that were going to pull and rubbed across my forehead until my fingers and my head were pretty darn cold.
I even went to pull again when I sat down but the urge had left me and I was able to not pull.
Does this work for anyone else?