Nicholas Brendon - "Buffy the Vampire Slayer" - boxer/briefs/speeos

In the only overt underwear scene on the show (with Nicholas) he is shown in boxers (He has a nightmare he shows up to school in his underwear) but ... in the last show of season 6 it sure looks like he is wearing white briefs to me. He is leaning over a hole and almost falls in. When he falls forward someone (or something) is pulling back on his pants so he doesn't actually fall (I doubt the viewing audience is supposed to actually register any of this - scene only lasts a few seconds). Anyway his underwear is fairly exposed and they look like white briefs to me (guess they could be boxer briefs but in my mind they aren't). Also threw in pics of him from episode where he was in a speedo.