I think sex appeal, magnetism and all that is just one way of putting it. Personally, I call it being likable. People with strong Venusian energy (for example, venus ascending, being near the ascendant, dignified venus..etc) tend to endear the natives to others. People simply like them. It doesn't have to be in a sexual, physical way.
Mars can show confidence in a chart. Confidence causes a radiance that people tend to drift to. Confidence can be everything in getting what someone wants like obtaining what you desire whether that’s a person, job or general things.
Mars can come across hot in that case. Not always but sometimes it does. Aspects help.