POS bowling
From Backstage Lore Wiki
POS Bowling was a technique in which a player warped a large ship such as a Titan or Mothership into a hostile POS in order to push out hostile ships in said POS [1]. The technique was invented by Against ALL Authorities and later perfected by Band of Brothers.
CCP later released a patch that among other things made it impossible for hostile ships to warp into a POS unless they have they starbase password for the POS.
Legality
At first this technique was deemed to not be an exploit by CCP but this decision was later reversed [2].