Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: how do you drink from the tumbler?
Document: Great tumbler, looks great, works as described, and easy to drink from. I left at contigo tumbler home and using this one now!
The picture shows the tumbler with the marking so you know where to drink from, but they're still sending the old tumblers.. its a great tumbler but you cannot see where to drink from.
I just love this tumbler. I put water in it and shook it upside down and it did not leak. I also like that I don't have to find the hole to drink out of.
Excellent thermos tumbler. These really last a long time and they keep drinks hot all day. Even in the winter sitting in a cold car the drink stays warm for hours. The mechanism works well and they are easy to clean.
Eventually I gave up and went with the thermos vacuum travel tumbler (SK1005MB4). That tumbler uses a lever to open the drinking spout and is easier to drink from. I am much happier with that mug than I was with the Sipp simply because of the superior lid design.
We bought this tumbler because it had received such good reviews. I'll start out by saying that it does keep liquids hot or cold for hours and when the lid is in the locked position, liquids don't spill. The problem is that there is what we feel is a serious flaw in the design of the lid. Both the lid and the opening that you drink from are both black.
To be honest, this travel tumbler keeps my beverages slightly TOO hot - if this is even possible. It's amazing how well it does the trick, but at times I would like my tea to cool down so that I can actually drink it! It is also slightly heavier than I would like.
I absolutely love this travel tumbler. It keeps my coffee warm for hours and I love the look of it. The only thing I would say is that it is hard to see the opening of the mug so I put a little sharpie mark on it so I know where to drink from. :)
I purchased this tumbler to replace one that I purchased in a store however lost. I received the tumbler when promised and in the condition it was reported to be (new). I would highly recommend this tumbler to anyone who commutes or travels and takes a hot or cold drink with them.
I bought this tumbler as a gift for my husband. He use it for both hot and cold drinks and this tumbler keep the drink hot/cold for hours. I got surprised when I opened this tumbler to clean it and find the ice cubes not melted yet after more than 10 hours.
Answer: There are two slits, one on each side of the top that screws into the Thermos. There is a button in the middle that leads to a spring loaded disk that seals the flow of liquid. Press to open, press again to close. Here's a link to some pictures: http://imgur.com/a/4ZRyL