[ Do It Yourself (DIY) ] Open Question : How to cover the sharp side of a blade on a knife?

I want to practice some balisong butterfly knife tricks because i am new to the hobby. I do not want to risk injury. Is there anyway to cover the sharpened side? It still needs to open swiftly, but be safe that if it hit my finger it would not cut. thanks

Source: http://answers.yahoo.com/question/index?qid=20130213015915AAcWMds

Lindsay Lohan Natalie Portman Nicole Kidman