Cock block American British vulgar slang
To prevent someone from succeeding in sexual activity attempt
I hate my sister's boyfriend, so I will cock-block them so that they don't get any action.
James invited his girlfriend to his house for having private space but his friend's sudden arrival cocked block them.
The verb "cock" should be conjugated according to its tense.
The term appears to date at least to 1972, when Edith Folb documented its use by urban black teenagers.
People tend to like forbidden or illegal things just because they are forbidden or illegal.
He must have believed that stolen fruit is the sweetest, and he, therefore, cheated on his partner.