The 108th Indianapolis 500 is goin' down this weekend ... which means someone will be dousing themselves in cow juice to celebrate winning the whole thing -- and a former champ is giving TMZ Sports the lowdown on the best milk for the job!!
One of the coolest parts about the iconic race is the post-race festivities ... when the big winner chugs from a massive jug of dairy to commemorate the milestone.
The Indiana Dairy Association works alongside the race organizers to keep the tradition alive ... with three options to choose from -- whole, 2% and skim.