Tanking basically means playing in such a way that your team will not be promoting in the next season as long as finish below 7th position by theory..(but recently some 8th place still could promote if T11 boss see your team quality has same level with the top 7)..

The goal of tanking is the managers could strengthen their team in the level they want to stay in, they have extra a month or more to prepare for the next level, basically a team that has finished tanking the season is usually stronger than teams that don't tank and they can win the championship next season or finish top 4.They also can save more tokens/cash/all packs for the coming season that they want to take part in...the more you tank the stronger ur team are...