Peer, according to the oxford standard dictionary, is defined as a set of people within the same age group as someone. Pressure on the other hand, is defined as the act of coercing or forcing someone to do the will of others. In all, peer pressure can be seen as a situation whereby a set of people/someone is coerced, forced or manipulated to do something against his/her will. Peer pressure can be in the form of sexual exploitation, cultism, vulgarism, exam malpractice, addiction etcetera.

http://www.trendsofnaija.com/2015/07/peer-pressure-what-youths-need-to-know.html