Your looking for mini swimming pools.
Store Location
#1 outside: in something purple
#2 outside: sit on a swing and rest a while
#3 outside: Still not rested? take a nap on a bed
#4 main floor: look for some sand...
#5 3rd floor: taking a nap again you see red...
#6 3rd floor: take the stairs
#7 4th floor: time for an impromtu snack, have a seat
#8 4th floor: try a snack at this table now
#9 4th floor: third dining set is a charm
#10 main floor: look to the center
Taken from the store itself. Theres also a direct LM giver but I don't do that on here so if you want to do that you will find that near the entrance of the store itself.