Toilet seats super loose in our '08 Dynasty Renaissance IV

What kind of toilet do you have? If it is the Tecma macerator toilet, the only way to tighten the nuts on the two bolts is to reach behind the toilet. Depending on how its installed, you may have to remove the bolts holding the toilet to the floor, pull the toilet forward to gain access. The original nuts used on the Tecma are strange looking wing-type nuts that are hard to tighten with most common tools. I replaced my seat recently and used 7/16" hex nuts so I could tighten them with a 7/16" socket.