Decorate cake. Use tip 16 and light blue icing to fill in ears and muzzle with stars. Use tip 16 and light blue icing to cover paw pads with swirls. Use tip 12 and black icing to pipe ball eyes and nose. Use tip 3 and black icing to pipe outline mouth.
Use tip 16 and green icing to fill in shorts with stars and overpipe edges. Use tip 16 and dark blue to fill in bow tie area with stars and overpipe knot. Use tip 12 and green icing to pipe outline suspenders.