Pancha Samskaram is one of the defining doctrines of the Sri Vaishnava tradition. One becomes a Sri Vaishnava only through Pancha Samskaram, commonly known as samasrayanam, at the hands of an acharya. Pancha Samskaram is a five-pronged ritual comprising Thaapam, Pundaram, Naamam, Mantram and Yagam.
Thaapam – Embossing of the impressions of the Lord’s Chakra (discus) and Shankh (conch) on the right and left arms. This is to make us remember forever that we are subordinates of Bhagavan Vishnu and enable us to identify ourselves with Daasathvam (servitude) to Him.
Pundram – Wearing the Dwadasa Pundras (12 Thirumans) at the specified places which are considered the abodes of the 12 Vyuha forms of Bhagavan Srihari Vishnu and their corresponding consorts on our body.
Naamam – Submitting the name as “Ramanuja Dasa” to enable one always be aware of his subservience to the Lord through the great acharya.
Mantram – Initiation into the three most important mantras in the sampradaya – Ashtakasharam, Dhvayam and Charama Shloka – considered as Rahasya Trayam.
Yagam – Initiation into the procedure of Thiru Aradhanam (puja) which needs to be performed by Sri Vaishnavas daily.
The acharya connect is quintessential in this regard. That is why it is called samasrayanam (samayak + asrayanam), which means “the good acts of attaining (a preceptor)."
These rules are followed by certain Hindu communities in South India who are staunch devotees of Bhagavan Srihari Vishnu.
Source – as told by Srivan Satakopa Sri Ranganatha Yateendra Mahadesikan (current and the 46th Jeeyar) of Sri Ahobila Math.