Quite right, I've just looked at it again myself. Jose plants his left foot and then his right leg swings round and catches Aguero on the ankle. Aguero has seen it coming and is already putting on his agonised expression before the contact is made. The tell-tale sign that he is making the most of it is that he makes no attempt to get over the incoming challenge but actually swallow-dives over the incoming leg and throws both his arms back. Having said that it was a 'trip or attempt to trip' and should have been a penalty but Aguero's theatrics were enough to persuade the ref otherwise.