<human>: Summarize the given text in a few sentences.

So yeah, happened a few hours ago. Our walls are mega thin, and you can literally hear someone typing through the walls.

My flatmate had his girlfriend over, and she is very vocal when she is being "pleasured". Anyway I heard a lot of noise last night, as per the norm, and this morning when my flatmate walked into the kitchen, I smiled and gave him a knowing wink as to what he had been up to last night. 

Fast forward until after she leaves, flatmate and I start talking, and conversation turns to last night, he says "Couldn't have sex because she was on her period" (never stopped me, but other people obviously have a problem). I was a little confused because of the vocality, and I replied, "Oh, so why was she making all that noise then?"

Now we've discussed her noise making before, so it's not really an issue. He says "Oh she was giving me a blowjob."

Now I was very taken aback, because never in my life have I heard a woman moan as loudly as she did, whilst giving a blowjob. 

I scoffed and said, "What?! Was she using your dick as a microphone for PornHub's new Singstar game? No girl would be that vocal during a blowjob, mate. I think she may be having you on..."

To which he told me to fuck off in a seemingly genuine manner, and haven't seen him since.
<bot>: flatmate's gf was loud, turns out it was during a blowjob, said I think she was faking, flatmate pissed.