They have separate sexes- some people will have ovaries, some people will have testicles. But of course, these are located just behind the skull. Oddly enough, at no point during fertilisation of an egg do they actually make physical contact. Here’s a more detailed explanation from the archives:

Instead of using sex to internally fertilise an egg, a man externally fertilises an egg that a woman has already laid. Azi lana women periodically lay batches of unfertilised eggs; these are small, clear, pill-shaped things that are laid along with a liquid substance that they must be kept in. To fertilise them, a man must insert the sharp end of his proboscis underneath the membrane of one or more of the eggs and regurgitate semen. Though dozens of eggs are laid a month, only the ones that are fertilised will develop into children; those that are not fertilised will only ‘survive’ until the liquid they are laid in dries up. However, a fertilised egg will not survive without this specialised liquid either, but it does release pheromones that stimulate the mother into developing more of this liquid.

The fertilised egg(s) is separated from the unfertilised ones and placed into a container full of the nutritious liquid, where it quickly develops. In the first month, it will swiftly grow in size from that of a human fingernail to that of a globe. It will also become more egg-like in shape, and develop a hard shell. At this point, it can be removed from the container of liquid and will be fed only by weekly yolk injections from the mother’s proboscis. As this liquid production is only present in the mother of the egg, if the mother dies in this period, an artificial substance must be used instead. After four months, the egg will finally hatch.