When our ultrasound technician got to that point, she told us that she was measuring the lower body and to look away if we didn't want to know the sex. We wanted it to be a surprise so we looked away.
But honestly, I could never make head nor tails of anything in those bloody ultrasounds in the first place that I'm not sure it would have made much of a difference if we had snuck a peek!
That said, it's entirely possible you were looking at something of a non-winky origin. Those ultrasounds are like one big mess of a Picasso sometimes. A Picasso on CRACK.