During the length of a 60-minute game, players can get hungry but there's usually not a lot of food available, especially when you're on the bench. In a pinch, apparently stick-blade tape will have to do.
OK, so even though it looks like Bieksa is ravenously biting into his stick as if it were a delicious extra crispy chicken leg, he was just trying to fix the tape on his stick. Without scissors around to help he had to improvise and resort to his teeth.
Thankfully he still actually had teeth to use but surely that couldn't have tasted very pleasant.
S/t to @Dr_Habs