Camille, I've so enjoyed the class.  Thank you!  I lead a worship team and play the keyboard as I sing.  I've often wondered if pressing the keyboard sustain pedal with my right foot significantly hinders my singing by not completely having a straight posture.  What do you think?  Thanks again, Donna.

Glad you've enjoyed it, Donna! 
As long as you're relaxed, I think you're good. Many singers play instruments while singing and it actually helps them to get in the zone and sing well. Good question! 

Donna, many many recording artists use their instruements when they sing. It is very common. I play the guitar and piano when I sing. I think they aid more than hinder. Just make sure whatever instrument you are playing that you are not hunching over. Be mindful and aware of your posture, body position, head and neck.