If a man gets a BJ or HJ from a Lady different from the person with whom he’s involved in a relationship, it may not technically be cheating if they have a permissive arrangement that allows intimate sexual contact with other partners.
However, if one partner in a relationship has any kind of intimate sexual contact with a third person that they must conceal from their partner, then it would be considered cheating.
In addition, masturbation might be considered cheating because that partner is depriving their significant other of a sexual activity in which they are engaging unless they requested their involvement.
Although, one of our former presidents got a BJ in the oval office and said he never had SEX with that woman, but he obviously never heard it referred to as oral SEX even though he was an attorney. 😉