In Jainism, "rasna indriya" refers to the sense organ of taste—the tongue. Controlling the rasna indriya is considered important for spiritual progress because attachment to taste can lead to passions (kashayas) such as desire and attachment, which are obstacles on the path of liberation (moksha).

Here are some Jain teachings and practices on controlling the rasna indriya:

1. Practice of Aparigraha (Non-possessiveness):

- Limit your attachment to sensory pleasures, including food. - Consume only what is necessary to sustain the body, avoiding indulgence in taste.

1. Observing Vows (Vratas):

- Lay followers (Shravaks) take the vow (Anuvrata) of limiting luxurious food. - Monks and nuns (Sadhu/Sadhvi) follow stricter vows, often eating simple, bland food and avoiding variety.

1. Fasting and Dietary Restrictions:

- Regular fasting (upvas), partial fasting (ekasana, biyasana), and limiting food intake help reduce attachment to taste. - Avoid eating after sunset, as per Jain dietary rules, to minimize harm to microorganisms and to develop self-restraint.

1. Mindfulness and Moderation:

- Eat with awareness, recognizing food as nourishment rather than for pleasure. - Practice detachment (vairagya) from the pleasures of taste.

1. Reflection (Bhavana):

- Contemplate on the impermanence of taste and its role in binding the soul to the cycle of birth and death. - Recite and remember teachings from Jain texts that highlight the importance of self-discipline.

1. Living Example of Jain Ascetics:

- Observe the lifestyle of Jain monks and nuns, who strictly regulate their diet and avoid any preference for taste.

Scriptural Reference: The Jain text "Tattvartha Sutra" (5.21) mentions that control over the sense organs (indriya-nigraha) is essential for spiritual progress.

Summary: Controlling the rasna indriya in Jainism means cultivating self-restraint in eating, practicing non-attachment to taste, and following dietary rules and vows. Through mindfulness, fasting, and reflection, one can gradually overcome attachment to the sense of taste, aiding in spiritual advancement.