Sure it's easy...just pour the beer with a of force and you get a big head. That's the theory behind the nitro pour. You can push the beer with a lot of pressure without having the nitro overcarb the beer. Before Guinness went to nitro, it used to come packaged with a syringe (really!). You'd suck some beer up into the syringe, shoot it back into the glass and bingo...big head! To me, the downside is that it strips the carbonation out of the beer.