i got Morgan's paw print tattoo'd on my wrist when she was 13 weeks old.  I used non-toxic children's black paint.  First I shaved the hair out from in between her pads, put some ink on her foot, and then pressed it a few times onto a piece of paper.  Took that paper to the tattoo artist and he sketched the best one then tattoo'd it on my wrist.  Took 15 minutes.  I love it.  
http://www.yorkietalk.com/forums/alb...&pictureid=116