AMAB and masc presenting.
I’ve gotten really into formal wear lately and am experimenting with how-far-is-too-far when tailoring one’s slacks especially close. I’m loving the fit of my slacks where I have them now but I can notice the line of my cotton boxer-briefs even when they aren’t bunched up. The loose cotton also has a tendency to roll/bunch when I put my leg down a pant so I’m definitely looking to buy a different solution soon, wondering which options might be best though.
They make thongs for mascs. Jockey has some decent ones, they don’t show in tights so your trousers should be fine.