Hi, Kadie!
As it happens, Adeniums are neither monoecious nor dioecious. Monoecious plants, such as corn, have separate male and female flowers on the same plant. Dioecious plants, such as holly, have separate male plants and female plants. Adenium flowers are perfect, meaning both male and female reproductive parts are contained within the same flower.
Images can be found here:
https://adeniumlove.wordpress.... along with instructions for manually pollinating.your Adeniums.
I'd also like to take a moment and address the term "self-pollinating". This term is generally used to indicate a plant type either will or will not readily produce seed without outside intervention. But I think it is important to note that just because a plant
does not self-pollinate does not necessarily mean it cannot produce viable seed from pollen from the same plant. Most plant types will accept their own pollen and produce fully viable seed, but there are those that will not. I can't think of an immediate example, but there are plants that require the pollen donor to be genetically distinct.
So in that sense, although Adeniums do not auto self-pollinate, they
can be manually self-pollinated.
