My friend who was d is extremely promiscuous?

Back when this girl told me she was d i believed her, but now im not so sure because i basically witnessed her thowing herself at my guy friend... and she wouldnt stop. What imwondering is... are girls who are d extra promiscuous sometimes or what... this girl has been a little off in the head her whole life... when the guy said no to her she wouldnt get the hint (she was like grabbing at him and stuff)... and that same night she was hitting on this other guy... we were all drinking but she wasnt drunk. The next day she claimed she didnt remember anything but i knew she was lying bc she mustve been embarresed. Im kind of weirded out by her and my friends dont like her. I feel sorry for her, but i also dont like hanging out with people like that... its embaressing. Im starting to believe that she overexaggerated about the after this incodent, or maybe the '' caused cause her to act this way .