Yes, you can go in just a little bit. Personally, I prefer to submerge my head just to make it "official". If you've never done it before, there's something important to know: Once you go in over your waist (and especially if you dive under the water), the cold collapses all that nice warm air inside your lungs and promptly takes your breath away completely. That was a bit of a surprise as I knew it'd be cold, but I didn't know I'd be breathless and cold when underwater.
