The first story can be found in Valmiki Ramayana: Uttara Kand: Sarga 31. After that incident, Kubera's son Nalakuvera cursed Ravana:
[Nalakuvera said:] O fair one [Rambha], since thou hast been ravished by him [Ravana] despite thy unwillingness he shall never be able to get by an unwilling damsel. Whenever he shall, stricken by lust, ravish a reluctant ...
Swami Vishwananda's answer explained very well.
For Grihast persons, best way is to imbibe supreme learning into long term memory by listening an audio chapter before sleeping, it will even help sound sleep and consistency in learning the Divine truth better.
Link to the audio chapters in English-