As a matter of fact, sometimes people do funny things to make life easier and fun. However, it would not be wise to cross your eyes from time to time. Maybe there will really be some impacts on your eyes. So, I suggest that you reduce or quit the habit. However, you will not be that serious though. But you really should not do this, which would give rise to painful eyes and headaches.
I have to admit that you are so funny and full of imagination, that's good for you.
But you can fell release to know that you won't permanently get crossed eyes by your small tricky. But as the old proverb goes "every coin has two sides", if you do that so often, I mean once hour by exaggerating, your eyes will get uncomfortable soon or later. However, your eyes would get exercised if you do that in a moderate way.
On top of that, you can get the conclusion of that don't do that so often.
Yes, you may get the permanent crossed eyes if you keep on crossing your eyes too much. As we know, the crossed eyes are born to be when you are a child. However, many people get this in the late environment. You should not cross your eyes for fun or you should not learn from the person with crossed eyes.