[forum post re: do you wear anything else? and a specific post extolling the pleasure of a half slip over silky panties]
i'm almost entirely about the feel of it. i'll wear just about anything considered lingerie or women's underwear/bra. if a dress or skirt feels good, i'll wear it. and the only reason (mostly) for wearing is the "looseness" or "tightness" while i masturbate with it/them. on rare occasions, i'll pick an "outfit" and the look is somewhat of an attraction. but is very secondary to the jacking.
the one exception is high heels. at one time i used to stuff the bras but don't really bother with that anymore. (just had to ditch the stuffing to rub myself on the material!) sometimes i get the craving for pantyhose, and a big part is wearing panties over them for the "combo" feel like the slip and panties. i like thigh highs because it seems to focus and accentuate the panties.
most of the time, it's just the panties. preferably satin, or the stretchy nylon-lycra type. i love florals and patterns, but am just as likely to use solids. i'll go with color over white almost always (harder to see the cum!)
a lot has to do with what's available. i've accumulated a few that are now "mine" but mostly use the wife's (no, she doesn't know). while not unheard of, i usually shy away from cotton, lace, and mesh. i'll usually pick any sort of brief, bikini, or boyshort (my fave on a woman!) over a thong.