upnover is right. Two-point and light seat are different. Some people will call both a two-point, but I prefer to differentiate. I've also heard people use 'half-seat', but I'm never quite sure which they are referring to, and there are probably other terms too.
It gets extra confusing when you've got people from different countries on the board. To use hotredrun's example, I've never heard anyone British use the term 'founder'; we all say 'laminitis'. And most people here don't even use the term 'two-point', but just 'jumping position' - I've started using 'two-point' all the time just because I spend a lot of time on international forums.
I would never say a light seat should be 'rolling forward onto your crotch' or anything of the sort though. No effective riding position should be described as that. Sounds like something you see in the ineffective, falsely posed HUS riders.
(and before someone goes postal, no, not all HUS riders, but there are a LOT that fit that description)