I had a minor foot injury. I used that as an excuse i.e. I told my friends that I have a foot injury so please don't give me bumps.
What are birthday bumps? According to Agent TBY,
At 12 A.M., your friends come to your room, take you out, and give you bumps (if you are healthy enough, they scold you for their soles got hurt). Then the cake comes, out of which only 25%(or less is eaten). After some time your friends apply Toothpastes, creams, powders, liquid soaps, etc. and finally buckets full of water. This normally continues beyond 2 A.M..they bump u on ur *** the number of years u've been alive
This is what happens at hostels/boarding schools.