while playing 2-2 i was going through the quicksand in front of the first checkpoint . i decided to hit the check point and then go through the sand. when i did this i died some how after this making a mistake. but i did it again. it let me keep getting the blue coins. once you get to the bottom hit the a button as long as you have more than one person doin this you can through over and over again. just turn into a bubble at the bottom instead of going through the pipe. just dont forget to hit the checkpoint first. or else this wont be very effective. now i have four people doin this. we get on average three lives per time.