OK .....so

You need another wrench to get the pump out of the seat tube.

You need to wipe the grease off before using it.

You need to have a grease rag with you.

You need to thread the pump through the spokes to get it on the valve because the seat is in the way. OR... you need to take the seat off first. Which will take another wrench.

If the "seat post" slips down you could damage the air fitting.

If you get or have another bike, unless it uses the same size seat post it won't work.

COOL...

Did I miss anything?