I am aware of your biological make up, inmate Hiling Care. The technology within this facility for this procedure is more precise and more trustworthy than the limited science of your world. Given the nature of some inmates and previous experiments conducted upon the population, the system will take no chances.
Behaviors permitted between licensed partners include penetration of any kind, cunnilingus, fellatio and other stimulation provided from one partner to another to the point of sexual climax.
All other inmates must make do with self-gratification in order to achieve climax. While the use of one's hands to provide external stimulation, the use of foreign objects and the use of one's tongue and lips externally should be acceptable, provided the other regulations are followed. Physical contact with another inmate while achieving climax is prohibited.