I think Magellans sells disposable undies. If you absolutely positively refuse to wash underwear, get the kind you can throw out. That way you'll never have to deal with them again.

Or instead of disposables just buy some cheap ones & throw them away.

I still think the blended cotton/poly Stafford brand (use to be Towncraft) from Penny's is the best choice. They are as lightweight as any men's full cotton briefs and my husband loves his so much that he wears them everyday.

Since I do handwash on our travels, the cotton/poly blend dries easily overnight.

I think the ones at Penny's, when not on sale, run $20 for 5 pair.

http://tinyurl.com/2d9pmj2

Mr.Piggy usually wears polyster/elastine mixed boxers from Under Armour. They are very light weight and marketed as performance underwear, but Mr.Piggy wears them when he's playing tennis or dressing up. Zegna also has great light weight underwear made of very soft thin cotton.

My husband finally bought some ExOfficio nylon/spandex briefs and likes them. REI also has them. On sale $12-15 per pair.