Need packer recommendations for high-impact sports and stunt work + secure attachment methods?

Hello everyone.

I'm looking for a packer that is about 3.5-4.5 inches long. A little longer or shorter is also acceptable.

I don't need an STP (I have the Axolom Uncut Willie, but I get far too nervous to wear or use it in public. The probability of spilling on myself feels too great), but I'll get one if it matches everything else I need. I'm looking for something that would definitely pass a "grab test". I prefer uncut but cut works as well.

Problem is I am a very active person. I can't afford to, nor do I want to, switch out/sew all my underwear to have an isolated packing pouch (it makes me dysphoric to need one vs just regular men's underwear). I'm a martial artist (Muay Thai kickboxing and jiu-jitsu) and soon I will be starting training to be a stunt man.

I need a packer that would definitely pass a grab test due to the intensely close contact of these sports. I have been able to get by because I was pre-T at this gym and most people thought I was a masc lesbian if they noticed I was not endowed or just assumed I'm a teen boy or something(which I am, so). However, I'm moving to a new gym soon and would prefer to pass completely as I do in every other aspect of my life.

It also needs to stay incredibly secure to my body (I was thinking maybe KT tape paired with a jockstrap? could work for this). Really just no possibility of flying out of my pants or shifting when I get blown the fuck up, thrown off a moving vehicle, doing backflips, literally anything you can think of.

Any product suggestions would be helpful, and I especially need help with packing techniques to make that sucker look and feel realistic in my pants but have no risk of moving even an inch. Thanks.