Multiple Perls is straightforward, provided you have a separate place to put them. I use /usr/local/perl/$VERSION to keep Perls (I have a 5.00503, 5.6.0, and 5.6.1 there). By default, most *nix use /usr for a base directory for Perl. When Configure asks you what you want to use a base directory, be sure to use something other than /usr, and you wont clobber your Debian install. Proceed per the instructions.

Be sure to invoke your new perl specifically by full path, or set PATH in such a way that it finds your new Perl first.

That's all there is to it.