ahhhh.. I can't log in, but never mind.
May I correct you guys?
That move is not exactly Teep. You may say that it's a kind of Teep, but there is a specific name for it. It's called Bata Loob Pak (foot touches face, and Sawatdee got this part right.)
I'll explain as the following.
OK. let's me say something straight forward. There are two kinds of Muay Thai:
1. Modern Muay Thai. It's the type that you guys see on the stage.
2. Ancient Muay Thai (we call it Muay Boran) as you see in the movie performed by Phanom Yeerum
Nowaday, it's hard to find somebody know about Muay Boran. But there are still few people who know it (I have done many reseach about Muay Boran). In Muay Boran, there are many major strikes(called Mae Mai) and minor strike(Luke Mai). Bata Loob Pak is one of the minor strikes.
In ancient time, if somebody was attacked by this move, he will end up with surrendering. It means that the guy who is being attacked has very poor skill. How poor? So poor that the opponent can bring the lowest part of the body to touch the highest part of him. And one more reason. The opponent could kill that guy, but he would not. Just let the poor guy lick on his foot. Those reason bring the surrendering.
Now I am going to talking about Teep.
Teep is the an action that the fighter execute by using his foot's palm (I don't know how to call it) hit any part of the opponent. Yes, Bata Loob Pak is a kind of Teep. But practically when we call teep, we refer to attacking oppponent's chest or ab to push oppnent away. And for this part, Okies has already explained.
There are lots for about Muay Boran to learn. And Muay Boran itself has many styles. For now I have heard there are 3 major kinds of Muay Boran.
1. Muay Koratch (heavy fist, tough strike) For this kind of style, the fighter will have rope cover from his hand to almost his elbow.(As we saw Phanom in the fight in the stage with the Burmese boxing) because he has to use arm to prevent powerful kicking strike.
2. Muay Lopburi (clever style) This kind of Muay Boran is hard to find now. From my knowledge, some said that it's already gone. So sad for me.

.. One more this. The fighter will wear the rope from hands to the middle of his arms.
3. Muay Chaiya (good move) This Muay Boran is originated from Pranakorn(that's how we call Bangkok in the old time). But this style has been settled down in the south of Siam (Thailand). It evolves lots of grappling. So the fighter will wear the rope just from this hands to his wrists.
4.(In the near future) Tony Jaa claimed that he is going to invent his Muay Boran Style called Muay Phanom. I think we are going to see it in the movie, too.
Wow.. lots of typing.