From Halopedia, the Halo wiki
Bloody Thirsty! is an achievement in Halo: The Master Chief Collection. It us unlocked by finding and destroying the BLAST soda can on Bloodline in Halo 2: Anniversary multiplayer. The achievement is worth 5 Gamerscore and can be unlocked in both matchmaking and custom games, though the latter is much more advisable. It also unlocks the "Bloodline" Multiplayer Emblem.
The can is found sitting on a rock in a crack in the canyon wall off to the side of blue base. If the player is standing on blue base looking to the center of the map, the can is on their left.