Its when they start yodelling that you need to be worried.
ahaha.
ive had a few weird ones in my past, one was english and sounded like she was in pain, i didnt give a sh*t tbh, once id had my fun i asked how she was.
one sounded like a baby laughing, that was messed up, but i had taken some hardcore drugs that night.
One was a plain old screamer, screamed the house down, my ears were actually ringing and i had to apologise to the neighbours the next day and explain she wouldnt be coming back.
But in my opinion its worse when they just lie there, silent, makes me think im humping the matress or something.