Diddy raped a woman at his Manhattan apartment, but the woman said she was actually relieved when he whipped out his penis … because she knew it wouldn’t hurt that much due to a lack of length and girth — at least according to a new lawsuit.

The Bad Boy Records founder is being sued by a Jane Doe who claims they met in May 2001 … she says they hung out a few times without incident at his Manhattan recording studio, night clubs and a restaurant — but things went south in July 2001 on their fourth meeting.

She claims after a night out at the club, Diddy took her back to his apartment … leading her to his bedroom, where he locked the door and pushed her down onto the bed on her back, placing his hand around her throat and telling her, “I’m going to suck the life out of you.”

In her suit, she recalls feeling “relieved” by the size of Diddy’s penis … claiming she knew it wouldn’t hurt as much when he raped her due to a lack of length and girth … saying she thought his penis was “an itty-bitty Diddy.”

The woman claims she screamed for Diddy to get off of her and stop and told him she didn’t want to have sex … but she says he overpowered her and did not stop penetrating her until he was close to climaxing.

She claims he pulled out and ejaculated on her body. She says he then backed away from her, and she slid off the bed and went to a bathroom to wipe his semen off her.

The woman claims when she exited the bathroom Diddy was naked on the bed, and she ran for the door and unlocked it. She says a bodyguard was standing outside the room and she asked him where the exit was, and he gestured downstairs. She says she left the place and Diddy’s staff drove her and her friend home.

She claims Diddy called her a few times after the alleged rape and even invited her to one of his white parties … but she says she did not respond to his calls.

Since the alleged rape, the woman claims she’s found it hard to be vulnerable and alone with men and has withdrawn and become a shell of herself. She also claims she needed psychotherapy to confront and address the trauma and move on.

She says she’s suffered physical abuse, emotional abuse, trauma, injury, and psychological damage as a result of Diddy’s actions.

The woman is going after Diddy for damages.