This is a simple and easy way to fake a positive result pregnancy test. There is no other way to make a pregnancy test come out positive every time without being pregnant.
Step one is to obtain a fake pregnancy test. The cheapest ones are for sale on ebay but fake newspapers has expensive ones. I can only personally recommend the ones on ebay.
One you get the test in the mail, tell your mark that you think you may be pregnant. It would help if you try to hide your most recent period.
Urinate in the cup and dip the pregnancy strip into the cup. Wait for the test to come up positive. Most test results can be read before ten minutes or so, depending on the test.
Show the test to your mark as proof of your pregnancy.
(optional) Act shocked and repeat the test with another fake pregnancy strip.
(optional) Cry a little bit or behave emotional. Pregnant women have a lot of hormones that cause them to behave more emotional than normal.