A blunt nose slide is a Wheelie done on the front and side of your snowboard. Doing the same trick on the rear of your snowboard is a switch-stance blunt nose slide.
The two key elements to this trick are the wheelie and the slide. You must be very proficient at both before trying them together. A slide is fairly easy to get the hang of and mostly likely is how you first learnt to stop on your snowboard. As you are riding down a gentle slope, turn to traverse the slope in such a way that your heels are towards to slope. As you make the turn lean back towards the slope to make the heel edge of your snowboard dig into the slope.
A wheelie has a lot to do with the balance and control of your snowboard. The easiest wheelie to do is on the tail of your snowboard. Begin by riding down a gentle slope, relax your rear leg slightly and stiffen you front leg. Lean backwards and raise your front leg up in to the air in order to raise the tip of your snowboard off the ground.
Now we put these two elements together. Traverse a gentle slope with the heel side of your snowboard biting into the slope a bit. This will help to stabilize you for the next part. Begin to put your weight on your front leg and then pull your rear leg up. This action will leave you riding on the tip and edge of your snowboard and looking really cool.