Any interaction involving two or more people that results in the sexual arousal/pleasure/fulfilment of the parties involved. Usually, in person, but now commonly occurs through texting, social media, web chat, etc.
a stimulating, passionate, and arousing experience with another individual in a romantic/sexual context. According to Segen's Medical Dictionary, "Any act between 2 or more persons involving sexual contact with genitalia and/or oral mucosa"; Meaning, anything ranging from sex to making out.