elvis on Jan 6, 2017 at 7:28 AM
Yes, it's likely that this is just a shift that comes with age. I wouldn't stress about it too much unless you notice other changes in your penis too. It sounds normal to me.
In my line of work, I see this often, I see this when the individual masturbates, excessively, or there thoughts wander from the task at hand, no pun intended. try to listen to tantra music, let your imagination run for a bit, and take your time enjoying the process,keep in touch and let me know how the tantra and thought technique may have helped, I can give you other suggestions, if you continue to struggle.