Is there a good way to straighten a tail tank on a midget , that has been squashed in by the bumper? Can you apply some heat or air pressure to help pop it out?

I have used heat

Evidently it's plastic, or it would be broken. You can set it out in the sun, and see if it'll pop back out, you can make a "pry bar" of sorts out of 2x2's and make a leg to push on the dent, or you might find a body shop with an air powered dent puller, and try that, if it hasn't been that way very long, it's "memory" will make it want to pop out, with the heat from the sun. Just a few things I've used over the years. Bob

Watch using air pressure... You can split the seams if you get too carried away.

I've been able to get them to pop out using air and setting it in the sun on its own not much pressure just let the sun do it for you.

Using the the sun for heat then use some air pressure should take care of it.

Thank you Gentlemen

Fill tank to the top with fuel. Then set in sun.

depends how bad it is but you can get most of it out with a heat gun.
we had a real bad one that i took the bladder out of, hung it from a fence so that the back of the tank was pointing down and then filled it with water and left it there for a couple days, occasionally hitting it with a heat gun at the dented spot. i saw donnie schatz's dad drill a 1/4" inch hole in the tank right back from the fuel plate and stick in a small air nozzle....blew the dent out pretty quick...and it was a pretty good size dent....

I used the sun and quite a bit of air pressure over a couple hours time, and help from dead blow hammer and it came out real nice. Thanks again for your help.