I would like to know if pushar is also used in Spain and is it only used by teenagers ?
I think you are trying to say "PUJAR". Pujar, from the verb "Empuja" meaning push in english, is used in Spanish when we are related to an expulsion of something out of a body, mostly our bodies. Therefore is commonly used for women giving birth and people who are expulsing a kidney stone for example. "Empujar" is used as to push something outside of our bodies.