I took some notes about this stuff a while back. I’ll just copy and paste the most relevant parts for you.
Flamingo LP - Hwoarang’s only 3f normal. It can be used to make frame traps tighter, but unlike his other light attacks, it does not lead to safe chains on block.
Flamingo MP - Two-hit attack that does twice the damage of a normal medium attack. Using this in combos generally always increases damage.
Flamingo HP - Can be used to anti-air, but its main use is in combos.
Flamingo LK - The animation is the same as standing LK, but the move properties are altered. FLA LK has shorter range than 5LK, but it starts up in only 4f and hits low.
Flamingo MK - Can be used as a poke, but it is mainly a combo move.
Flamingo HK - Has good range, but it whiffs crouchers and has long startup and recovery. Its main use is in combos.
Tsunami Kick > Flamingo (6MK > 6) - Unlike Hwoarang’s other Flamingo transitions, this does not cause him to recover faster at all. However, he still ends at +2 advantage on block, making this a useful option for pressure. FLA LP and LK make good frame traps here.
Low & High Smash Kick Combo > Flamingo (5LK > MK > 6) - Recovers 8f faster than normal (+2 on block, +7 on hit). It is useful for comboing into FLA MK > LK because it forces the opponent to stand.
Reverse Kick > Flamingo (5MP > MP > 6) - Recovers 8f faster than normal (+2 on block, +7 on hit), but it’s not usable for pressure or combos because of the pushback. You can input 5MP > 5HP~MP at mid-range to option-select the string on whiff while also buffering a 5MP-5HP boost combo (especially on crouching Sakura) and hold 3 or 6 to recover as fast as possible.
5MK > MK > 6 - Recovers 8f faster than normal (+1 on block, +6 on hit). On block, it can be followed with FLA LK for pressure. On hit, it can link into FLA LK or MP for a combo. You can also use this in certain juggle combos to connect 2MP or 5HK afterwards.
Quick Kick Combo > Flamingo (FLA MP > MP > 6) - Recovers 5f faster than normal (0 on block). This transition is needed to connect FLA HK afterwards.
Flamingo Kick Combo (FLA LK > MK) - This string has a Flamingo transition, but it is not useful. It is better to cancel to Dynamite Heel on block. Hwoarang moves forward, so he can easily keep pressure on the opponent.
Fire Storm > Flamingo (FLA MK > LK > 6) - Recovers 4f faster than normal (+4 on block, +6 on hit), but whiffs most characters crouching. It is very useful to pressure large characters who cannot crouch under it. You can also use this in certain juggle combos to connect 2MP or 5HK afterwards.
Edit: Added formatting and corrected some misleading info.