Mississippi Code Title 99. Criminal Procedure § 99-19-21

(1) When a person is sentenced to imprisonment on two (2) or more convictions, the imprisonment on the second, or each subsequent conviction shall, in the discretion of the court, commence either at the termination of the imprisonment for the preceding conviction or run concurrently with the preceding conviction.

(2) When a person is sentenced to imprisonment for a felony committed while the person was on parole, probation, earned-release supervision, post-release supervision or suspended sentence, the imprisonment shall commence at the termination of the imprisonment for the preceding conviction. The term of imprisonment for a felony committed during parole, probation, earned-release supervision, post-release supervision or suspended sentence shall not run concurrently with any preceding term of imprisonment. If the person is not imprisoned in a penitentiary for the preceding conviction, he shall be placed immediately in the custody of the Department of Corrections to serve the term of imprisonment for the felony committed while on parole, probation, earned-release supervision, post-release supervision or suspended sentence.