A toddlers diaper should be tight enough so that the diaper is not falling down around the waist and the diaper should not have gaps around the legs.
If the diaper has gaps around the legs or is falling down then the diaper is too loose on the toddler.
If a diaper is too loose the diaper will usually sag and fall down and there will be gaps between the legs.
Make sure that the diaper fits snugly around the waist and thighs by running your fingers around the edges and checking that there are no gaps.
Diapers that are too loose will slide down the babies or toddlers bottom and leak.
When you put a diaper on the baby or toddler the diaper should be tight enough to not fall down but not too tight.
You should be able to insert 2 fingers easily under the diaper waistband of the diaper when it's tight enough.
To tell the front and back of the diaper just look for the tabs of the diaper.
The tabs of the diaper are on the back of the diaper and those tabs reach around to the front of the diaper.
To put a diaper on a baby or toddler place the diaper under the baby or toddlers bottom with the tabs underneath them.
Then pull the front of the diaper up between the legs and then use one tab to secure the diaper and then use the other tab to secure the other side of the diaper.
The tabs are always on the back of the diaper.
Diaper Tabs should not overlap or reach and touch each other when the diaper is sized right.
If the diaper tabs overlap then the diaper is likely too big.
The diaper tabs should ideally just reach about 1 inch to 2 inches over the diaper landing zone and there should be at least an inch or so of space between the diaper tabs.
Or if the diaper tabs do not reach at least an inch onto the diaper landing zone on the front of the diaper then it may be too small.
Tight diapers on your baby or toddler should not cause constipation.
However when the diaper is too tight then it can cause the baby or toddler to become uncomfortable cause rashes and red marks around the child's waist.
Tight diapers can also make it hard for the baby or toddler to move around especially if they are walking it can prevent them from sitting down or bending over easily.
So the diaper should not be too tight anyway and if the diaper fits tight then you may need to change diaper sizes and go up a size larger in diapers.
You should be able to fit 2 fingers easily in the diaper waistband between the diaper and the child's waist.
Your baby or toddler may not be getting enough fluids which can lead to constipation.
Most cases of baby constipation or toddler constipation go away on their own within a week or so but if not you should take the baby or toddler the doctor.