Volcel if you wouldn't
Volcel if you wouldn't is a phrase used to challenge incels to declare their willingness to have sex with an unattractive individual, or to accept unpleasant conditions for having sex (such as accepting cuckoldry), under penalty of otherwise forfeiting their incel status. "Volcel if you wouldn't" is often posted in response to photos of, e.g., severely deformed females, extremely morbidly obese females, and MtF transsexuals.
Hypothetical scenarios are also sometimes presented, often jokingly, e.g. in a conversation about mother-son incest, "Volcel if you wouldn't."
The exact dividing line between incel and volcel can be blurry, due to the controversy about whether incels can have standards and still be incel. Most notably, some say that if an incel refuses to be a literal cuck, but insists on having a female to himself, or insists on a virginal bride, then he is volcel.