Strip him naked, in front of a bunch of prostitutes, let them fondle him, then slowly slice each testicle out of the sack, then cut each one off, one at a time, show it to him, then toss each into the toilet and flush...
All the while he is hanging just high enough off the floor to keep from choking to death...right away...
Then let the blood flow...slowly from the wounds...castration first, then "Bobbit" the bastard...
A slow, degrading, death...by prostitutes...
And I'm sure there will be plenty of volunteers...