From how to command a room -- "When they walk in they just feed this presence," Jacob said -- to how to impress a sold out crowd -- "I've turned into an amazing dancer on stage" -- the 17-year-old has learned a lot opening for the group.
But when MTV News asked the singer the most valuable lesson he's taken away from his time with 5H, we weren't expecting this from his answer: "My twerking skills have improved times 12 at least," he laughed.
While a jam packed tour schedule hasn't allotted Jacob a ton of quality time with the ladies of 5H, he said they do hang out whenever they get the chance.
"The other day we all sat down and had an awesome jam session and we jammed out to Beyonce and Ed Sheeran," he said. "I played guitar and Camila sang and all of them came in and started harmonizing and it was like, 'Oh my God,' like, I forgot how to play guitar all of a sudden."
One reason for Jacob's abrupt case of amnesia could have something to do with a little puppy love he has for one of the members.
"I've definitely been crushing on Camila," he confessed. "I'm sorry Fifth Harmony fans don't hate me, it's just a crush, I don't look at her don't worry. I can't make eye contact."