Haley Kalil‘s well within her rights to talk about the Coke cans her ex Matt Kalil‘s packing in his pants, her lawyer says … because she has erotic autonomy.

Matthew Bialick — Haley’s lawyer — tells TMZ … he plans to file a motion to dismiss Matt’s lawsuit within three weeks of being formally served the summons or complaint, which hasn’t happened yet.

Bialick says it’s totally unreasonable to file a lawsuit on the basis of making someone liable for “exercising her sexual sovereignty by truthfully describing a sexual experience that left her in tears” … adding it violates his client’s right to free speech.

ICYMI … Haley revealed on a podcast her marriage to Matt was marred by his massive member — which she described as two, maybe three stacked Coca-Cola cans.

Matt then filed his lawsuit … claiming Haley’s suit attracted “unwanted attention and invasive commentary from the public” while his family had “been forced to endure the ongoing public circulation of these degrading and deeply personal statements.”

Matt also accused Haley of growing her follower base with the comments … thereby unjustly enriching herself — while his current wife became the subject of “increasingly frequent, disturbing, and alarming” messages.