Madison Parker's either throwing serious shade at her ex ... or she needs to see a doctor about short-term memory loss.

Aaron Carter's ex-GF was outside Blind Dragon in Weho Friday night when our guy asked her an interesting question about Carter's sexuality ... that she clearly didn't want to answer.

It seems like there's bad blood brewing between the 2 since they've split -- Aaron told us Madison walking out on him was a gut-punch -- and now she's referring to him as an enemy.

On the bright side -- Madison tells us she loves everyone and prays for the best, and Aaron says he's doing great ... in the oral sex department.

AARON'S PARTY
TMZ.com