Give your bestie a bracelet that is finished off with a knot that's as tight as your friendship! Use a simple over hand knot...you know...the one that looks like a pretzel? For extra precautions, loop thru the center twice before you tighten up the slack with a double overhand knot. If it's a bracelet you want to take off, try a slip knot.  It's a little tricky at first but with practice you will get the hang of it.