Try a Jockstrap they're comfy trust me. Or Bikini briefs, or go up a size,or try a different brand that's softer made of smoother fabrix
Briefs shouldn't hurt unless you're wearing the wrong size. MAybe your legs are more muscular? I usually wear briefs and don't usually have that problem unless they're too tight. You might try sports briefs.
Try a larger size. Or. Go for bikinis I been wearing bikini ( mens)for years and like them best.
R U really so delicate that u feel lines of brief when u sit? I think u r extolling