You can use float - 1 after b2 anywhere on the screen and combo after it.
Can be done mid combo, start of a combo, end of a combo. In effect it allows you to get another 'rep' of b2.
For example;
(With trait)
B2, DD1 - 1, dash, B2, DF1B, J2, B2, DF1B, J2. 296.98
B1 - 1+3MB, B3, J3...