Ink tool: can I make it get thinner instead of thicker?

[tolworthy]

I love the ink tool (the calligraphy pen): a slow movement is a thick like, and a fast movement is thin, just like using a quill pen. But for drawing I need the opposite: when quickly drawing a person's arm I need a thick line, but when I slow down to draw the fingers I need it thinner. Is there some way to do that?

(Using Gimp 2.8.16 on Linux Mint)