If he's a clean, decent looking guy that obviously takes care of himself, AND will allow me to suck his cock too, there's no way in Hell I'd turn him down!
In a heartbeat! At the top of my list since the first time I tried it with a bi couple. Then I had a live-in girlfriend that fell in love with MMF. She taught me to be passable and we'd go out together finding men to share.
The opportunities are much less frequent at my age, but I still love to orally service couples before, during and after they've fucked.
First purchase was feminine, but not exactly clothing - more like an intimate accessory. All of my teenage clothing came from my sister or a friends older sister. Then my sister started getting a semi-annual box of hand-me-downs from my mom's friend that had a daughter that was older and larger than my sister. My sister wasn't at all fond of the idea and would cherry-pick an item or two and let me have anything I wanted and I got excited when that included a couple of training bras. They were big enough to fit me but I had nothing to fill even an A cup bra. My sister said I had to buy some falsies at a nearby dept. store.
I think I stood outside the dept. store for an hour working up the courage to go in and by a set of falsies. I tried to use the excuse that I needed them for a joke and the sales lady began scolding me for wanting to embarrass some young lady and to stop her I admitted I really wanted them for myself and when she didn't believe me, I showed her I was wearing a bra. At that point I think she may have been more embarrassed than me, but I bought them and got out of there in a hurry.
In weeks to come, I became a regular customer of sorts and always visited other areas of the store until I was sure the sales lady I'd met was the one in the lingerie area and she wasn't busy.
Blow buddy in my teens. We convinced ourselves (without much effort as I recall) that if I dressed in his sister's clothes and pretended to be his girlfriend, we weren't really doing any of that 'queer stuff'.