What makes a good whaletail?

This may actually not be a good whaletail, believe it or not

 So something I was discussing recently, what makes a good whale tail?

It sounds silly but I think everyone has a different definition. I think the thing about whale-tail that makes it hot is the seductive SUGGESTION of hidden sexuality being revealed. Regular pants represent a regular reality and the thong represents sexuality just hiding underneath. 

However a lot of whale-tails you see online now are girls that show most of the thong, the pants look like they are pulled almost all the way down and the thong is fully visible. This is sexy no doubt but it isn't suggestive. Lets look at some examples of what I mean. This is from user janabellok on reddit: 

If you think about the balance here, on one side you have the thong itself and the other you have the level of suggestion. This pic definitely leans in the thong direction but it is low on suggestion. Not bad at all, very sexy , but not the best sort of whale-tail. 

Lets look at some better examples. This is Dreadgorgana on reddit.

Here we see much higher suggestion. I think the key is that you shouldn't see the full thong. It has to feel like either an accident or a plausibly deniable action, not full blown showing because that's too on purpose, when it can be enriched when teasing dynamics come into play. 

On some level I think my overall point is that a whale-tail is not just about the thong but about the relationship between the thong and the pants/skirt etc. They combine to promote suggestion, its not just a showcase of the thong. I want to see a women who is suggesting to me that everything I want is just hiding below the surface...I love that tension and juxtaposition.