As a Finn, I can confirm that people draw vulvas, although I don't know if they're more popular than dicks.

The doodle is usually called kirkkovene ("church boat"). https://www.google.com/search?tbm=isch&q=kirkkovene&tbs=imgo...

(Screenshot, in case Google doesn't give the right results for all users: https://i.imgur.com/HASrhyr.png)