fretless intonation exercises

[ii7-V7]

I'm new to fretless bass. What are some exercises to improve intonation. I can only think of one thing to do and that would be to keep your tuner on while you practice to be sure that each note is in tune.

[Audiophage]

Check against the open strings.

[Martin Motnik]

A good practice is to play along with songs. You'll figure out fast whether you're intonating right! Keep it up and don't let yourself get frustrated! As soon as you handle the fretless right, you'll love that unique sound! Have fun!