It is very important to decipher what the underlying cause of your sciatic pain is before attempting any asanas, especially if you are experiencing severe pain in your lower lumbar spine; however, from experience with piriformis syndrome (that resulted from going too deep into bakasana), I will share what I found very effective for healing quickly and regaining feeling in my legs and buttock within a few days.
First, using a topical treatment like magnesium lotion or Traumeel can be very helpful in reducing discomfort. Alternating between heat and cold packs can also be helpful for immediate relief.
Second, it may be helpful to supplement your diet with natural anti-inflammatories like curcumin (turmeric) and omega-3 fatty acids (salmon, chia or flax seeds).
Third, the following asanas, if practised very carefully, preferably under the supervision of a teacher that knows you well, can ease sciatic pain and discomfort.
Also, because these asanas are all hip openers, you may experience a deep emotional release as the hips soften and dispel built-up stress, negative energy and anxiety.