Have you got any thing for it to climb on?
IMO hes just resting his head,ive got a couple here that do the same..By the way i dont think its a Coastal its a Port Mac diamond-Intergrade,a female i have here that looks the same,either way hes nice..
It looks like a diamond. What are the humidity levels ?
Some times the enclosure can be to small. My snake does it sometimes but she on roaming around and exploring. Do you have 2 hides on each ends ?
Is he feeding good and shedding good ?