coming in a girl's mouth

What is the cultural meaning of coming in a girl's mouth?
Do I wish to feed her or fill her mouth with filth?
Is it just to test whether she accepts my messiest mess
Or simply paint a funny milk moustache across her face?

Or is there in this thrilling ritual something messianic
Some sort of baptism by sperm?
Like my cock is John the Baptist saying
'One day someone greater than me shall come'
Or some Moses who leads an entire nation across her tongue
To liberation

Well that must be it, why else fill a girl's mouth saltily full
With a fluid the consistency of honey, tapioca, and motor oil?