Can be used as a faster way to say "all up in your business" but is not recommend in public. Originated from the nosy pepper joke. However this joke is to be used as a last resort or used to stall somebody. Although one can sometimes get away with using this term regularly.
unfunny friend: What do you call a nosy pepper?
wise friend: ...jalapeno business
unfunny friend: ......danggg
hipster guy: do you think Stacy likes me?
hipster guy #2: yea, dude, she was jalapeno business yesterday
hipster guy: ..cant believe you just said that
hipster guy: oh alright, cool, thanks