Why put pressure? Pressure will wear them. It tires them and forces to either take the pain or open up and make a mistake.
One of the most important parts of matwork that many Brazilian Jiujitsu practitioners fail to stress the importance of or see the value in the practice of is osaekomi waza also known as pinning techniques. Good osaekomi waza should make you feel the need to tap from the pressure.
Osaekomi-waza (Pinning techniques) is one of the groups of Katame-waza (Grappling techniques). These pins represent different types of hold down techniques when holds another one on his back.
The Side Mount (or ‘Side Control’) is commonly a favorite position for practitioners in the beginning stages of jiu jitsu, but is then often neglected in favour of the mount and back control.
When used correctly, these two principles will improve your ability to dominate and control and opponent from the side mount.