So you think blowing bubble rings is cool...

[Aquatic Eagle]

Similar technique to blowing cigarette smoke. Make an O with your mouth and blow out the air with your tongue in the middle of the lips.

That's pretty much how we did it. It just takes a lot of practice to get good at.

 

[Phrenzy]

I must admit that I am pretty good at it. What I do is fill my mouth with air and quickly 'pop' my lips open. I almost spit the air out of my mouth.

Give that a try.

 

[Monkey_Gland]

Make a sort of "wuuuah" sound forcing air out. Like the sound of a drop of water.

BTW Did you get a sneaking suspicion the dolphins were developing this as a means of escape. Teach the whole group..when they do it in unison it will have the force of a Streetfighter Dragon Punch!