In the business of the summer, I never recounted the content of my conversation in which I noted a striking connection between Christianity and sex. Actually, in retrospect, I should note that the connection is more between the Christian Life and sex than with Christianity per se.
The controlling metaphor that links the two is the recognition that while both are beneficial/pleasurable for the individual, the moment that it becomes "all about you," you miss the best of what they have to offer.
The Christian life and sex are ultimately 'other centered' activities...at least, in their best moments. Both can (and often are) pursued for personal or selfish reasons, but doing so misses out on the true and lasting benefits inherent in each. The more other-focued we become, the more we recognize that extravagent love stems not from our own pleasure/benefit, but in the recognition of the other as a worthy participant in the same.
Grace & Peace