Fans speculate over the quirkiest of oddments. What is the First's cup size? Would Giant/human relationships work? Did Cirrus Kindwind’s last name refer to her ability to produce musical wind, rather than her gentle disposition?
Similarly, most grave and vital questions about Giantish undergarment materials have floated up to the surface. Do they weave fabrics out of plant fibers and sheep’s wool, or do they only tolerate rawhide and granite against their unmentionables? Of course the Giantish skin is tougher than the tender equivalent of humans, and the Swordmainnir in particular wish to maintain their badass status - and let's face it, wearing stone skimpies would give anyone a bad ass - but one might deem they would appreciate small comforts at least, what with in any case leading a perilous and oftentimes rugged life.
The Giants kenned the arcane sciences of sailcloth fabrication during the 2nd Chronicles, and unlike the devolving Land-dwellers, later embraced new fashions. The sailors of Dire’s Vessel radiate sheer chicness in their canvas outfits! Hence the idea of regular linen braies is not unthinkable.
How would one proceed to craft granite knickers? One might sculpt them from a single boulder, but such a style would hamper mobility and prove most embarrassing should the unyielding clump drop down in the middle of action, for instance crashing onto someone’s head on the deck of a ship or imprison the legs of a warrior in the middle of the battlefield. The less weighty option is to link thin granite disks together to form a type of scale mail. This might actually feel refreshing against one’s bum on a sweltering summer’s day, but is not likely to induce laughter when the thermometer hits -30 centigrade...
Therefore, one might surmise that only the most musclebound swaggerers getting their kicks out of the fear-shivers of puny humans (e.g. Grueburn and Cabledarm) would resort to such 1337 tough-panties. Then again, the rumormill grinds tales about Grueburn always preferring a more or less healthy breeze behind the faulds, and that Cabledarm is so butch that she might well wear a sock instead (although probably also a granite one).