The Recent past tense refers to some action that happened a day or two ago.

अश्रौषम्
aśrauṣam
I just heard.

However, the difference between the ordinary present tense and the recent past tense is not quite clear yet. Different schools and communities of Sanskrit use their own way of distinguishing the difference. The main problem is that there is no parameter to measure the nearness of the verb.
Some examples of the stems of the recent past tense are given below;

Type Vowel change Example
Root None bhū → bhū
Vowel None gam → gama
Doubled None naś → nīnaśa
s  
sa Strong śru → śrauṣ
Sis hā → hāsiṣ
si Strong bhī → bhaiṣī

Past tense without –a prefix

Interestingly, when the a sound is removed from the verbs in ordinary and recent past tense it describes the words as “wishes” and “desires”. They more commonly appear in Vedas and other mythological scriptures and are used to give strong commands. The words used for this purpose is “ma”, “smā” which means “do not ever”

क्लैब्यं मा स्म गमः पार्थ
klaibyaṃ mā sma gamaḥ pārtha
You must not ever go to cowardice, O Son of partha (O Arjuna).Bhagavad Gita 2.3

माहं ब्रह्म निराकुर्यां मा मा ब्रह्म निराकरोत्
māhaṃ brahma nirākuryāṃ mā mā brahma nirākarot
Let me not denounce Brahman; let Brahman not denounce me. Upanishads (various)