Colonel Lillian "Lil" Rayburn was a character who appeared in the Season 7 M*A*S*H episode "Lil". The part of Col. Rayburn was played by veteran character actress Carmen Mathews.
About Colonel Rayburn[]
When Col. Lillian Rayburn visits the 4077th to inspect its nursing staff, she shows the medical staff, especially to Margaret and Colonel Potter that she's not your typical hard-nosed stickler for regulations: she's warm and friendly. She insists on being on first name terms with Margaret and spends time to encourage her, counselling her about her uncertainties and fears of being alone, given her problems with her husband.
Rayburn also seems to take a shine to Col. Potter, who is the only one in camp around her same age. They've known a lot of the same people, and immediately fall into telling each other stories from their overlapping past. Col. Potter and Lil - as he comes to call her - spend all their time together, sharing a bottle of scotch and going on a picnic.
Radar is not particularly pleased at the turn of events, feeling that this Col. Potter is acting improperly for a happily married man. Margaret, once she has a talk with Lil about her future in the Army, relaxes and recommits herself to a career in the military. They share their bi-polar feelings over some drinks in the "O" Club. After a few more days like this, Col. Potter and Lil only grow closer. One night, in Colonel Rayburn's tent over some booze, she makes a move on Col. Potter. Potter is stunned into silence, and has to awkwardly explain that nothing like what Lil expects to happen is going to happen.
Potter apologizes, saying that maybe he sent Lil the wrong message being so friendly - but he was just so delighted to have someone of his own age to pal around with. But as long as he has a woman at home waiting for him.
Col. Rayburn understands, and apologizes to Potter for misleading him; they then say goodbye to each other rather awkwardly but still friendly and amicably, as she plans to leave camp for the next MASH unit inspection the following morning.