I have these 2 male red ear sliders that flutter to each other frequently, much more so than to the females (almost never). I know that it can be a sign of friendliness/mating or dominance/aggression but they have never attack each other or seem aggressive with each other. Then today, I saw one of them mounting the other one and both of the male turtles had their penis out

. This is the first time I saw something like that. So, is it a dominance thing or can my turtles actually be gay? O.o