the act of a man intentionally and secretly taking off a condom (= a thin rubber covering that can be worn on the penis) during sex, although it had previously been agreed with his sexual partner that a condom will be worn

Stealthing is illegal in many countries because it is regarded as non-consensual sex. 偷摘避孕套在许多国家是非法的，因为它被认为是未经同意的性行为。