I found this on some asian forum I think;
http://www.soompi.com/forums/index.php?showtopic=321467HOW TO POOP AT YOUR BOYFRIEND'S HOUSE WITHOUT HIM NOTICING:
SOUND
This section is for when the smell is not a factor, but the sound is. For example, you know he wont be going into the bathroom soon (perhaps because he already went) but the walls are paper thin.
If appropriate, the best thing is to tell him you are going to take a quick shower. This is great because he thinks you are doing it as "prep" for "wowie time." Turn on the shower to mask the sound of plopping. However, beware of two things: 1: The smell will be worse in a humid environment so use cold water, and 2: do a super fast wash-up afterward because of the whole aforementioned "wowie time" thing he may be expecting.
Flush as you plop. Pretty self explanatory. If its not going to be super weird for you to flush four or five times, then time your plops to the same time as the loud flushing noise. Beware: TIME PROPERLY! The loud part of the flush is not for a few seconds after you've pushed the lever.
Put some toilet paper into the toilet before you begin. This absorbs the plop and thus prevents that telling back splash noise. Beware, it will smell worse if you use this method because the specimen is not submerged fully into the water.
Turn up the radio before you leave, saying that you love this song. Then after a minute of dancing or singing along, excuse yourself. Chances are, he'll leave the radio up loud until you come back.
SMELL
Smell is a tougher thing to conceal. But sometimes its all you need to worry about because the area where he is sitting is far from the bathroom and the sound wont carry. If this is the case, here are a few tips:
Use the bathroom spray or, barring that, perfume, BEFORE you drop one AND after. Most people wait until after. Do not make this mistake.
Crack a window or light a match, but these are both "tell tale poop smell" concealers.
If possible, wait to go until right after he goes. That way, the smell has a chance to dissipate by the time he needs to go in there again.
If multiple flushes aren't a problem, take advantage. The less time poop is sitting in the toilet, the less chance is has to stink up the room.
TIPS: If all else fails, accept that he will know you pooped. As unattractive as it might be, all mature men know that all humans poop. If he makes fun, tell him to grow up. If he won't grow up, he's not mature enough for a relationship anyway.
I thought it was funny.
Topic: How to poop at your boyfriend's house without him noticing