I didn't explicitly say "no" in the situation, but my inaction was downright heroic.
I've got a female coworker, and we're friendly, but I know she liked me more than being friendly. She's basically the same type as the last 2 girls who had a thing for me. Anyways, we're getting some food and drinks after work on Friday, and I go to drop her off afterwards, and it turns out she left her keys in the apartment, and her room mate locked when she left and she won't be back until tomorrow morning.
I say that she can just stay at my place, I've got a comfy couch (it really is comfy) and I can drop her off tomorrow morning after her room mate gets back. Well, she never even looks at the couch. She sits on my bed and we chat some more, and then she lays down and says "can we just cuddle, like, as friends?"
I'm not thinking completely straight, and I say yes. We end up sleeping in my bed all night (no couch). I know she's angling to sleep with me, the most explicit move was when her head was resting on my chest and she tilts her head up and kisses my cheek.
But here's the thing, despite the fact that I kind of like her too, there are two major things holding me back.
She's my co-worker, that I work closely with on a daily basis, and I usually try really hard to separate my personal and professional life. If things go badly at any point, we're still stuck working together.
She really doesn't have her shit together. Like, that room mate isn't an actual room mate, she's just staying there for the time being because she got evicted from her apartment. Earlier in the week she got drunk during lunch and was sent home.
So I know either way, this is not going to end well. So I just do nothing but keep cuddling, but not going further because I can't let this lead to what she's hoping it would lead to. And it worked, and somehow it's not awkward at work. I think maybe she thinks I'm gay now though, but that's alright.