Well when ever anyone goes and picks him up and it's not all the time. Dont think it's fear chucks fearless not afraid of anything, the younger one I keep with him is more nervous
Pick him up scratch his head or shell just interact with him
Without knowing additional husbandry you offer I can not just guess for ya....also, pairs are a hard thing to achieve...and if you already have a dominant tort and a "more nervous" one...I would also keep an eye on the nervous one to assure it does not begin to lose weight or the stop eating as much and stop basking and hide always....clicking alone ..if all husbandry is good, is not unusual from time to time....