actually there is no such thing as a presequitur, but there is a common misconcepton that there is something of that nature which exists. The Phallacy results due to an ignorance of linguistic derivation commonly known as ontology.
Non means "without"
sequitur means following
therefore non sequitur means without following
in some examples people mistakenly believe a presequitur is something that crops up from a previous conversation in a new conversation - but this is still merely a non sequitur
a) Dude are you sure about this presequitur business
b) oh absolutely certain - doesnt exist
a) fried eggs ?
b) hmmm what?
a) thats what i think we ate that on tabletop mountain
b) ahaha oh I get it you used a non-sequitur
a) yes to illustrate the point that its not a pre-sequitur