You will need:
1. A ruler.
2. A piece of string bigger than your normal waist size. (If you do not have any string spaghetti will do just as good.)
3. A paper and pencil.
What to do:
Before sex measure your midriff using the string/spaghetti and the ruler. Record the result on the piece of paper and store somewhere safe. Repeat the same procedure after sex, and subtract the two figures. The answer should be 0 (zero).
Continue the measurements daily, plotting the results on a graph: a consistent rise in waist size over a period of months tells you what you need to know.
© Steven Spielberg & Rob Gotobed March 2014