To Muslims, nothing is as bad as a pig! Captured Al Shabaab militants should be made to engage in bestiality with pigs (have sex) before they are shot and the recordings sent to them. Pigs are considered demonic and since they are lured with the promise of after life following a suicide, touching a pig will mean that they 'wont make it to heave'. This will deter them a lot.
Enjoy every moment of your life, you never know when your time will come.