To unlock the Token Gesture trophy in Borderlands 2, you will need to redeem 25 tokens.
You earn tokens by increasing your Badass Rank. To raise your Badass Rank, you will need to complete various in-game challenges. For each challenge you complete, you will be rewarded with a token.
To spend them, do your ECHO and select the Device tab. Redeeming a total of 25 tokens across different characters will unlock the trophy.