zooendoeurothophobia
Fear of having a foreign object, most typically an animal, enter the vagina without the permission or knowledge of the girl. This fear prevents sexual intercourse in a body of water, since that is the most likely activity to allow a "Zooendoeurothophobia" incident to occur.
zooendoeurothophobia: Sex in a lake and a tadpole swims up your v-jay-jay.