DMFI: Don't Mother Fucking Interrupt
Similar to LOL, or BRB or any other shorthand/acronym used on the internet; this may be used in conversation or online to give emphasis to the point that you would like someone to stop interrupting you.
Omar: I was on the dfloor as I do and..
Girl: OMG I LOVE THE DFLOOR! dancing is amazing I Once was...
Omar: DMFI Bitch. I'm Talking!...