Double jungle, oh it has been a while lol. There is two ways to do it, first you take a support style jungle (normally a tank) and a duelist jungler (someone like xin) and while the tank clears like a normal jungler the duelist set to steal the enemy camps. If done correctly the enemy jungler will fall quite behind and you double up the power of ganks to snowball. The drawbacks are numerous thou, first the bot lane will be a 2v1 which most adc won't be able to do so top and bot will have to switch if they want to keep an adc, so is adc vs bruiser and bruiser vs support and adc, it can be a tough match for the bruiser. Secondly if somethign goes wrong is even harder to catch up since you will have two champions without enough gold income to oppose as just one.
The second way is to get a top bruiser with smite, you start on the other side of the jungle and let the top(normally with a mid leash, or tp) take gromp/wolves or krugs (depending on side) that will give him an early level 2 which should help to snowball his lane, once you finish the opposite side whatever camp your teammate took should be back (you have to switch a bit the order thou because it will be back towards the end of the clear). Then on early game you give top a couple of kills/ganks to set him even ahead so mid game-ish (normally when they hit 6/7) they will start roaming the enemy top side of the jungle and steal the camps. The enemy jungler will fall a tad behind and also will force him to gank top more often which leads you to the opportunity of taking dragons and free ganks on bot. Again the drawbacks are sorta harsh, first if it doesn't work/top can't snowball he will be left with a useless spell. Secondly, is heavy dependent on a good top that knows what is he doing. third it requires comunication to avoid he top laner to get traped on the enemy jungler.
Most of the cases is not worthy on a ranked solo queue game as the risks are big