Flurry

When you use your bonus action to engage in two weapon fighting you rain a flurry of blows on your opponent.  You make additional attacks at increasing difficulty. 

The first attack of your bonus action is rolled normally.  If it hits you may make a second attack as part of your bonus action at -3 to hit.  If it hits, you may make a third attack as part of your bonus action at -5 to hit.  If it hits you may make  fourth attack as part of your bonus action at -7 to hit.  

The flurry ends after 4 bonus action attacks are made, when you miss a bonus action attack roll, or when your target dies.

If you are engaging in two weapon fighting and make and opportunity attack as part of your reaction you may attack twice.