Rawm is a special method of stopping in which the final vowel is not removed absolutely; a very faint, brief portion of it is voiced. Tradition often explains this as approximately one-third of the original vowel. The stopped quality remains dominant, but a slight audible trace of the underlying vowel survives.
This is not the same as saying the whole final kasrah or dammah. A full vowel followed by continuing to the next word belongs to connected reading; rawm is a carefully controlled reduced vowel at the end of the stop.
Its precise sound should be learned by listening to a qualified teacher. Merely reading a description should not lead to arbitrary half-vowel or full-vowel endings. Rawm hints at the original vowel; it does not create a new one.