A man is riding his dirt bike through the air in the desert.
A man is showing off to his girlfriend while doing tricks on a dirt bike.
WE have no idea if he is showing off for his girlfriend. We don't even no if there is another person with him or not. We have no idea if he is doing tricks or not, he could just be riding.
A man is riding his dirt bike doesn't imply he is showing off to his girlfriend.
The man is not showing off, no girlfriend is there and he is not doing tricks.