Continuing on the innuendo: topologically a vagina is not a hole, but a butthole is.

You could argue that a hole is an entrance to a wider space. A door or window is a hole to a room. If you want to know the number of holes in a room, you would at least have to include all the doors and windows.

In this sense, the straw doesn't have a hole at all.

Or maybe it is just one hole.

I think the solution here is to have a way to measure the tightness of a hole (of which something can be inserted)