Amazon has David Archy boxer briefs and briefs that do exactly this. Far less expensive than most of those already mentioned. Under $30 for a 4 pack. I use them and recommend.
If you care about having incredibly comfortable underwear and undershirts, have them buy you some David Archy clothes from Amazon.
These are made of micro modal, which is like this super soft, breathable material like bamboo/rayon. What's really special about these is the innovative design where there's a hole to stick the shaft of your penis through, so it doesn't stick to your balls. Your balls rest comfortable on this hammock, and there's also a ventilation flap to help air them out. I've replaced all my underwear with these and Manscaped Boxer Briefs, which I used if I'm planning on walking a lot, since they are anti-chaffing.
These are made of the same micro modal as the boxer briefs, and pair very well with them. With them, you get to feel the nice fabric from your knees to your waist. I have 10 pairs of them, and will always wear them when wearing the matching boxer briefs. The fabric is so nice that I won't wear them if I'm wearing my Manscaped underwear, since I'm not getting the full benefit of the micromodal on my pelvic region.
These are my favorite undershirts/pajama shirts. They're also micro modal, and feel amazing. I have 12 of them.
The only thing you need to be aware of is that these need to be washed in cold water, and tumble dried on low. If you use hot water or high heat, then they can stretch out. My wife washed a few of my undershirts on hot, and now they fit like tunics. I still wear them and enjoy them, but I look silly.