A few months and several more pleasurable encounters after that first amazing threesome, Sarah fell into some living trouble when her current housemates all found different places to move out, leaving her unable to afford the rent on her own. She had noticed, in all the extra time she'd been spending at our place lately, that our apartment had a spare bedroom we'd really only been using for storage.
It was a proposition we had to think carefully about. Moving in together as a couple had meant to be the moment both Katie and I stopped dealing with housemates and sharing accommodation. We were grown adults who didn't want to worry about privacy the way we used to.
But then, if it was just Sarah, we still wouldn't have to.
The rules were established quickly. We would keep sleeping together as a trio, but with the understanding that Katie and I were going to remain the couple in the middle of that. Sarah got her own room in case she ended up bringing someone home and the freedom to date and fuck whoever she wanted, provided she did so safely.
As for everything else, we just did whatever we wanted. Whatever felt right in the moment. The apartment didn't become a nonstop nudist orgy overnight or anything, but we got pretty damn casual about our bodies and libidos pretty quickly. Naked walks from bedrooms to the bathroom were done sans towels, and coming to breakfast half dressed in mostly underwear wasn't an issue. Doors were left open for changing, washing, masturbating and even fucking, with audiences and assistance welcome. When one of us felt horny, he or she would strip down and openly flaunt their body through the apartment naked, or in lingerie, harnesses and other gear that would enhance our nakedness rather than hide it, waiting to be taking up on the implicit offer. Open displays of arousal at what we saw were encouraged and often rewarded, usually right where they happened. I got blown, got jerked off, ate pussy and fucked in the living room, the kitchen, the bathroom and both bedrooms, usually with the other girl watching from the doorway. I would watch them the same way, joining in if I was invited and touching myself to the show if I wasn't.
The things I saw in the first week alone would keep you turned on for a year. I wish I could write up every individual encounter for you, but these things take a long time to type when I always end up having to do it one-handed.