It does sound like braxton hicks. You afre more likely to get them earlier because of the twins! Good Luck
I agree, it sounds like bh contractions and i wouln't worry unless they become regular (6 in an hour) and really painful. Your babies are also probably running out of room in there and causing pressure on all your organs and ligaments which can cause pain and discomfort. I know twins can come earlier than a single baby so maby mention it to your doc next time as at this stage in your pregnancy and with twins you should be seeing your doc every two weeks.
It could be Braxton Hicks contractions. They can begin as early as 6 weeks and it's a good thing! When it is NOT a good thing is when the contractions are persistent and consistent and painful. But a little tightening is normal.
at your stage, i imagine if it is not painful, it is them kicking you, or each other! when i hit about 25-27 weeks, i could see alex "grazing" across my stomach with his foot/knee.....now, i'm 33-34 weeks, and he drives me nuts, b/c my stomach will tighten, and all of a sudden, he kicks, then rubs on me....lol.....
How often does this happen and is it painful?