levels of training in Shambhala

https://shambhala.org/about-shambhala/the-shambhala-path/shambhala-training/
https://en.wikipedia.org/wiki/Shambhala_Training
https://shambhala.org/about-shambhala/the-shambhala-path/way-shambhala/

Level 1 is introduction to basic goodness.
Level 2 is the Cocoon of your own assumptions and perceptions.
Level 3 is warrior in the world. The emergence from the Cocoon is recognized. Change can be delightful.

I think it is possible to hold onto a feeling like love or compassion

Exercise 1a: Say the word "goat" out loud a few times.
Result: you can say the word "goat" repeatedly and thereby intentionally hold onto a verbal expression.

Exercise 1b: Say the word "goat" in your head a few times.
Result: you can say the word "goat" repeatedly and thereby intentionally hold onto an internalized expression.

Exercise 2a: Tap your finger on a surface.

Result: you can feel your finger intentionally for an arbitrary duration

Exercise 2b: Feel your finger without moving it or touching anything.

Result: With practice at interoception, you can feel your finger.

The purpose of these four exercises was to demonstrate that it is possible to hold onto a thought and a felt sense. Therefore, it should be reasonable to extend the practice to emotions.

Exercise 3a: Feel love or compassion by situational exposure

Result: you can feel love or compassion

Exercise 3b: Feel love or compassion by without situational stimulus.

Result: you can feel love or compassion

the value of a meditation retreat

I previously described the logistics of a meditation retreat, which takes a lot of work. That work has a purpose: to minimize the cognitive and emotional processing of the retreat participants.

A person has routines that are dealt with using patterns of behavior -- both in terms of thoughts and emotions. There are also ad hoc disruptions to the routine; these also are dealt with by the individual on a cognitive and emotional basis.

In order to disrupt the routine, it is displaced by the retreat routine -- scheduled meals, specified meditation times. To decrease the normal disruptions, isolation is used to ensure a person can sustain focused attention.