All I think you could do is a s3ven step process,
Uno. Stay logged on your DS
Dos. Get on a computer
Tres. Create an e-mail (make sure you remember your e-mail and login info)
Cuatro. Go to the Colors *D website
Cinco. Create a new account giving your e-mail
Seis. Get on your DS and post a painting saying what your new account is
Siete. Log in to your new account
This way, if you forget your login info, it can be e-mailed to you! Most online communities have this feature, so it can be a good idea if you share your e-mail (unless it is an untrusted site, then don't give your e-mail). Hope this helps you! ovo

Umm I forgot my password once. Go to the Colors3D website. On the login page, there should be a password-reset thing somewhere. That allows you to change your password. If that doesn't work, then I can't help... sorry. :(

How do you make a new account?

@Kirby "DS"

IT'S A FREAKING 3DS!!! :@

On the colors3D website, click my gallery (towards the upper-right), and something should come up telling you to log in, somewhere in the window, theremshould be something like: register or sign up. ovo

-PSTP the dragon
um... im sorry if DS offends you? o-o

is there a way to do it on the 3ds?

yeah, but you would have to log out, could you log back in somehow?

Not sure.... so if i log out then click on the gallery will it come up with a sign in or register thing?

@Kirby I'm sorry if I overreacted. I'm just tired of people calling 3DS a DS. It's like calling Wii a Gamecube.

If you log out, you can't log back in with this account again, but you could still register a new one. ovo

-PSTP Dragon
It's ok! I typed DS because i was worried the "3" in the 3DS would be censored. ovo

@Above Oh, I see. People IRL use to call my 3DS a DS cuz they don't know the difference between the two handhelds.