The term "heads trip" generally refers to a hallucinogenic or mind-altering experience. Antonyms for "heads trip" could include terms that suggest clarity of mind, sobriety, or mental stability. Some possibilities might include a sober reality, a clear-headed perspective, a rational approach, or a grounded outlook. Other antonyms might include terms that suggest banality or mundane reality, such as a mundane existence, a boring routine, or an uneventful experience. Depending on the context, antonyms for "heads trip" could also include terms that suggest a lack of comprehension or understanding, such as confusion, bewilderment, or bafflement.