Coming in dead last in a swim race, i.e you finish so much later than everyone else, it's embarrassing. the people who are clapping are just glad you managed to finish so the meet can continue. while they clap for you, you must drag your ass out of the water (if you can) or someone else will haul you out. This typically occurs during the 500 free.
yo dawg i ate a bagel w/creamcheese i can feel the lactic acid building in my muscles, i'm totally coming in clap last
A bag of treats given to one competing in an athletic event. (It's a -sack- that's supposed to -psych- you up.) Psych sacks are typically prepared by the team captain, or whoever's feeling generous/remembers to do it.
grab your psych sack & get on the swim bus ladiiiiiieeeees