I haven't worn any in months. Well, rarely I'll wear boxers, though I can't remember the last time I have done that, actually. A few months ago probably.
I got to the point where I was trying on pants without underwear on, and buying them to wear sans underwear, about a year ago, sometime in the winter.
The year before that I was in boxers or nothing, most of the time. What allowed me to transition was wearing an apron all day in the kitchen. I could get the occasional boner or something and no one would notice. Then I felt a lot more comfortable walking around from work to home, etc. Now I hardly notice at all, or enjoy it
It helps that I'm uncut.
I think my boyfriend likes that I don't wear underwear... he wears boxers though, probably because he is cut. Sometimes i bring boxers or shorts when i stay at his place to lounge around in, but that's it, we are half-naked around each otehr a lot of the time
