It is from this video. It is at 4 minute and 48 second. Here is the context:
The point is on the one hand when we describe what we are, we tap heavily into our own identity, the way that we would like to see ourself.
It is a figurative use of the faucet device that is placed in the bung of a barrel to allow the beer or ale or cider to flow out, though many speakers are no doubt unaware that they are invoking that metaphor when they use the word. For them it simply means "get access to".
Figuratively we can tap into anything that is a source of something that can "flow" out in a metaphorical sense.
We can tap into the electrical supply line behind the bank of elevators.
Dali sought to tap into the subconscious by depriving himself of sleep.
The definition for tap into something is:
to understand and express something such as people’s beliefs or attitudes.
I think tap here means this sense:
- verb. If you tap a resource or situation, you make use of it by getting from it something that you need or want.
For example, The utility group has launched the company in an attempt to tap into the market for green energy. [VERB + into]
I think that the phrasal verb tap into sth is used in the sentence with the following connotation:
to manage to use something in a way that brings good results.
You look into and use your identity just the way you would like it to be.