Baby favorite position

Last week and this week, the baby's movement are the most active. And this week, some 'strange' incident happened where out of a sudden, my tummy is one side bigger than the other(the weight suddenly rest on one side of the tummy). A bit hard for me to explain it and it does not happen in all pregnancies.

It is the baby, 'cuddle' in such a position at one side of the tummy (usually the right side, but i donno why..)When i put my hand on the tummy, i can feel it very 'hard' and as though i can 'touch' the baby( i still wonder whether it is the head or rump?)

Perhaps this has something to do with genetics. My mom said when she was bearing me, the same incident happened and she would lie down and let me 'relax' and later on 'swim' back to the middle of the tummy...:)