Looking for volibear advice for self and buddy

I own volibear and i play him occasionally, so i suggested to our team jungler to try him out since he's free right now (he's an amumu main) and he should add a high damage tank jungler to his roster to help him rank up. I already told him some things, but wanted to see if anyone had any tips on him that i may not of known to relay to him along with any additional things that a novice volibear and a first time volibear may want to know.

Situational items are pretty standard tank or tanky fighter items.