Aceness mode means: The state of fully embodying asexual identity or energy, often used humorously to describe switching off romantic interest entirely - whether permanently or just for the moment. Implies a. It carries sexual or vulgar connotations; not alarming on its own but worth understanding the context your teen heard it in. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.