When is the supplication made in Salatul-Istikharah or Salatul-Hajah? Is it after the tasleem of the prayer, or during sujood, or before the tasleem?

The supplication for Salatul-Istikhara (Prayer for Guidance) and Salatul-Hajah (Prayer of Need) should be recited after concluding the prayer with Taslim (saying "Assalamu Alaikum"). This is based on the Prophet's (peace be upon him) sayings in the hadiths concerning Istikhara and Hajah prayers: "Then let him say" and "Then let him praise Allah," after commanding to pray two rak'ahs. The particle "thumma" (ثم - then) denotes a sequential order with a slight delay, indicating that the supplication is to be made after the Taslim.