"Heart Shaped Box" By Nirvana
"I've been locked inside your heart-shaped box for weeks"
In this Kurt Cobain is trying to say that he is stuck in this relationship even though he know that it is hurting him with a metaphor.
"Rape Me" By Nirvana
Do it and do it Again
Rape me, my friend"
Kurt Cobain is using a metaphor to the emotional abuse he is getting from Courtney Love
"Lake of Fire" By Nirvana
"They go down to the lake of fire and fry"
Kurt again is making a metaphor to bad people going to hell.