This is hilarious and very hot! Imagine it must have been pretty awkward for you both at first, but what came out of the discussion? Did either or both find it arousing? When you say you became 'close friends' does this mean what I think it does?Walk-ins can be funny after the fact tho quite awkward at the time, bro/sis, parent, room mate, other relatives, friends, the severity depending on the activity one walks in on.
One for me was walking in on Tim, a dorm and classmate. We'd been assigned to work a project together, I showed up to his room an hour early for our second work session. He'd given me the code to let myself in, he surely wasn't expecting me that early. I was stunned to find him watching porn and in full stroke mode wearing a red lace thong while using another pink panty wrapped around his cock and headphones. (Found out later those were "borrowed" from the laundry room.)
Stunned is probably an understatement, what a sight he was. I was shocked and should have left but was frozen in the doorway watching. He must have realized the door had opened and spun to look just as he let loose the first shot. He froze and stared at me but kept shooting several more blasts without moving his hand.
Again I thought of running but being a curious person I had a dozen questions that needed to be answered too. No project work got done that night but I did get answers which brought more questions. He got more talkative about it the more we chatted and and calmed down. Even showed me the dozen or so items he'd "borrowed" from the laundry. None were mine, but I took the opportunity to point to a blue pair saying "These look familiar." His jaw dropped.
We did become close friends and finished the project several weeks later.