The night they slept together
Sure she was upset about Leonard and Priya, who wouldn't Priya was everything Penny wasn't, smart, successful, great career. Hell I'd pick her over me. But sleeping with Raj had nothing to do with the two, Raj was always attracted to her, mute and all, the wine did some talking but Raj saying those sweet things to her was all she needed to here and then he called her beautiful and she knew where that was headed, wrapped up in his arms the next morning. Lucky for her she remembers every detail.
She remembered kissing him and then going down on him and then him on her, then removing each other's clothes as she put the condom on him as she then got on top of him but at some point she did some crazy sex position even she didn't know, she was sure was going to be sore, probably some Kuma Sutra, then she remembers him getting on top and thrusting her as she felt her walls cave in as she climax multiple time before he did the same as she fell asleep with each other spooning.
Now as Raj is mute again they dress in silence and instructs him to act natural. He nods.
Oh crap Leonard is here and so is Howard, well might as well do the walk of shame while everyone is here.
"Morning guys." She says before making her way to her apartment as she hears Leonard asks what's going on.