A Blast Combo used by Goku in Raging Blast
Blast Combos are techniques introduced in Dragon Ball Z: Budokai Tenkaichi 3. They are a regular combo technique followed up with a Blast 2. Also, the Blast 2's executed at the end of these combo's do significantly less damage than a Blast 2 performed normally, but use a fraction of the ki that would normally be used.
For example, Goku performs a Rolling Hammer technique, then uses the basic follow up to that move, and after he knocks the opponent away, he quickly executes a weaker Kamehameha wave.
Mastering these combos is important if to fighting stronger opponents or giant characters.