How to be a better punching bag?

I play teamgames with a few friends quite often and in those games I am usually the target by more than one enemy because of my own aggressive play at the start as flank or the dangerous civ choice. More often than not, this means I get overwhelmed after my initial rush by more than one player. This is not a problem as long as my team kills the other side faster than the enemy can kill me. I want to get better at this part as now I'm feeling like I lost the game for my team when I did not hold the line on my side.

What are your tips for defending as best as you can? Do you have any videos with good examples? How to be a better punching bag and win the game for your team?