Well, castration is a reality – for various reasons, including for example cancer. Sexual thrill is not high ranking on this list.

For information on orchidectomy you could peruse the Eunuch Archive message boards. The thread on Consequences of Castration covers various health topics, such as osteoporosis.

And emotional topics: depression!

And sex related topics. Just one quote: 'Do not assume you will still want to be a sub, bottom, slave, or whatever. Such activities are part of sex, and sexual feeling. You may still want to hold someone, or be held, but that is a far cry from actively wishing to please some one else sexually. And frankly, when the idea of sex becomes as attractive as taxes, chances are your partner will notice and lose interest.'

If castration is a sexual fantasy of yours, you could perhaps take a look around their story archive, where it is just that. A fantasy. http://www.eunuch.org