Literally, “do the cobra”. In reference to the way cobras react when they are attacked - by leaning backwards.
hacer la cobra (first-person singular present hago la cobra, first-person singular preterite hice la cobra, past participle hecho la cobra)
- (idiomatic) to pull away (from a kiss) by leaning away; To back away (from a kiss) by leaning away
2016 November 2, “Este vídeo te obligará a reconsiderar si Bisbal le hizo ‘la cobra’ a Chenoa”, in El Periódico[1]: