Cavalier SNORTING ........ I assume.. ?
I think it is 'snorting' that you are referring too but the 5 minutes would be very extreme.
The best thing to do is one hand at the back of the head and the other over the nose holding the jaws shut while tilting the head downwards.
This, if you count to 5-7 will normally stop the snorting.
It is a characteristic of the breed (so im told) that should not be worried about !
However best check this out with a Vet - just incase there is another issue ongoing ?