N.M.
He is exploring his world. He doesn't really understand your attempts to control him and if you settle for controlling his behavior and upsetting yourself, you are setting up one heck of a hard relationship.
He is suppose to explore his world. He will put things in his mouth. You are not here to control him and since you are the adult you have to accept that this is normal behavior. It is not something to be upset about.
Look at the energy, he gets attention, we all love attention and he gets to put things in his mouth. You have to get over your emotional reactions or you will suffer with this child down the road.
Time outs are cruel and punishing, no one really learns from them even if they modify their behavior. You should never give time-outs. We will find out that they are the cause of much emotional/mental damage in a few decades. Just like Dr. Spook's work was discredited when his son committed suicide.
Make his zone safe. He will grow out of his oral fixation. You have to look at how you where treated - where you controlled w/frustration?
Give him room to explore.
If there are safe zones and then places like outside that are off limits this is easier for him to understand.
When you are upset, to him this just looks like mom being silly. And at 2 retaining information that is against his nature for 20 minutes - is not bad. You do not want him to grow up w/all this negative energy between you two. I have seen it and it is a pattern of you controlling him that will lead to him bullying or being a bullied.