The phrase "in tumescence" refers to a state of arousal or sexual excitement. Antonyms for this phrase might include "flaccid," "unresponsive," or "uninterested." When someone is not in a state of tumescence, they might be feeling indifferent, apathetic, or even repelled by sexual stimuli. Other antonyms for "in tumescence" might include "calm," "sober," or "dispassionate." In general, antonyms for words related to sexuality or arousal tend to be more clinical, dispassionate, or negative, as there is often an association between sexual desire and emotional intensity, pleasure, or excitement.