Megan Fox Spills on Past Plastic Surgery & Drinking MGK's Blood on 'CHD'

Megan Fox says her paranoia surrounding surgery has been her saving grace in not going under the knife too much ... even though she admits she's had quite a lot of work done.

The actress appeared on Wednesday's episode of "Call Her Daddy," where she opened up about all her plastic surgery experiences -- including a lengthy pre-op routine she says she requires all her surgeons to follow, 'cause she wants to make sure there's no bad energy.

MF says she responds poorly to general anesthesia, so she demands that her doctors tell her if they've seen any bad omens before cutting into her ... take a listen to what those are.

On the actual procedures themselves -- Megan admits to having had three separate boob jobs, and insists she's only had her nose worked once, despite what some people think. She also teases a mystery surgery she's had as well ... but wouldn't disclose what that was.

Megan also says she's considered a BBL -- but notes she doesn't have the body fat for it.

Anyway ... there was more Megan talked about -- including the fact she and Machine Gun Kelly drink each other's blood ... which has been accused of being Satanic.

Megan defends the practice here ... saying it's a lot more innocent than folks think -- likening it to two kids putting their bleeding thumbs together on the playground when they think they've found their "soulmate." She says she and MGK share that kind of bond.

She's also got a pretty graphic comparison in making her point -- saying she finds girls who engage in oral sex so freely to be way more gross than anything she's doing with her man.