I transitioned in 2007, and until a few months ago, I was tucking almost everyday, but I started having pelvic pain, so I stopped. Two weeks ago I found a small lump on one of my testicles, which thankfully is benign calcification, and since I have a few of these smaller calcified nodules inside of the testicle, I have to get another ultrasound in 6 months, but the prognosis is good, and my Doctor is not worried, but he wants to be proactive. I didn't feel comfortable talking to him about tucking, but I will talk to my primary care physician about it.
I may have been tucking the wrong way, since I did not place my testicles inside of the inguanal canals, I just placed everything between my thighs, and pulled my underwear up to secure everything, and since my package is small and it wasn't uncomfortable, that's the way I did it.
It is extremely important for us to do self exams on our breasts, and if pre-op, our testicles also.