Rapper Mystikal's porn career is off to a promising start -- TMZ has learned, Mystikal's #1 porn star crush has AGREED to have sex with him on film ... but he better not plan to get paid for it.

XXX star Pinky -- who Mystikal named as his top choice to pop his porn cherry -- tells TMZ, she's flattered the rapper picked her ... and will gladly film a sex tape with him for her website.

But Pinky says she refuses to pay him -- because Mystikal is currently an "amateur" and Pinky doesn't pay amateurs ... "no matter how good he is in bed."

As we first reported, Mystikal says he's taking one last stab at the music biz before he gives up and turns to porn ... seriously.

As for his six-year prison stint for sexual battery, Pinky says it doesn't bother her one iota -- telling us, "I think he came out looking better than when he went in."

Mystikal is giving music one last shot -- but tells TMZ, if he fails to make another hit on his next album ... HE'S TURNING TO PORN.

This is not a joke. Mystikal tells us, he needs to make sure the money keeps coming in ... and if there's one thing he's good at, it's having filthy sex. So porn is his plan b.

Which is either crazy ... or perfect -- because Mystikal served SIX YEARS in prison for sexual battery beginning in 2004 after forcing his hairstylist to perform sex acts on him.

But Mystikal is undeterred, telling us he already has a history in porn -- winning an AVN award in 2003 for an adult movie he made (he doesn't actually have sex in it though).

We asked Mystikal who he'd want to star in his first skin flick, and the rapper said Pinky -- adding, "She's a bad bitch. I would take her down in a second."


As for whether he's got the requisite hardware to be a male porn star, Mystikal wouldn't give an exact size, but said, "I'm definitely the man, the myth, and the legend."

Mystikal is a free man ... after spending more than 2 months in jail for violating his probation ... TMZ has learned.

The "Shake Ya Ass" rapper was released from the East Baton Rouge Parish Jail in Louisiana early this morning ... where he had been incarcerated since May 14.

As we previously reported, Mystikal was sentenced to 90 days behind bars after being arrested for domestic abuse ... a violation of his probation from a previous sexual battery and extortion conviction.

Rapper Mystikal -- famous for his 2000 hit "Shake Ya Ass" -- just checked into a Louisiana jail this morning, where he's expected to serve out the rest of a 90-day sentence for domestic abuse.

As we reported, Mystikal -- real name Michael Tyler -- was arrested in Baton Rouge on a domestic abuse charge back in February, and a judge ruled it was a violation of his probation. The circumstances surrounding the arrest are unclear.

Mystikal was put on 5-year probation following a 6-year prison stint for sexual battery and extortion.

Mystikal pled guilty in 2003 to forcing his hairstylist to perform oral sex on him.

The judge has already given Mystikal credit for 9 days served while he was detained following his February arrest. He has 81 days left.

Former No Limit rapper Mystikal -- the guy behind the 2000 hit "Shake Ya Ass" -- is going back to the pokey ... all because of a domestic violence arrest back in February.

Long story short ... Mystikal was put on probation in 2010 after spending 6 years in a Louisiana prison for sexual battery and extortion. So when he was arrested for domestic abuse in February, the judge ruled it was a violation of his probation.

Now, Mystikal -- real name Michael Tyler -- has been ordered to spend 90 days in jail ... beginning on May 14.

"Watch ya'self."