What Is The Lightest And Heaviest Thing In The World?

Teacher: what's the lightest thing in the world?

Student: sir, it is penis?

Teacher is shocked, but still curious

Teacher: how?

Student: it can rise just with an imagination

Teacher: Nice! So which is the heaviest thing in the world?

Student: Penis again sir

Teacher: what nonsense, how can penis be lightest and heaviest at the same time?

Student: because after couple of fucking rounds, even an earthmover or a crane can't erect it.