Using beer pressure instead of peer pressure cause you're not 16 anymore and the situation generally involves absurd amounts of beer.
Your buddy won't straight arm a beer cause his mom just ironed the shirt hes wearing, so everyone starts yelling at him and screaming beer pressure till he's becomes a man a does it.
1. "I didn't want to smoke last night, but I was totally beer pressured into it and couldn't say no."
2. Mike: "Dude! Why did you take that girl home last night?" David: "It was beer pressure, I swear!"