Nexgen unfortunately lacks speedos and stuff like that mostly just underwear. There was a jockstarp model however over here if that helps

https://mega.nz/file/M5gxDJwC

Also petruz has some models with underwear that can sorta look speedoish I think I usually go with wolf pack:
https://www.furaffinity.net/view/35042985/

Although they can be a pain sometimes to get onto the males body but they have some bulge options as well. Hope it helps

Thanks a lot. I was playing around with them but figured I'd ask if anyone knew if better options.