Write the start of a sexy smutty story that will be continued using further user prompts, don't end of the scene with a conclusion yet.
Wisened human healer NAME_1 is travelling with his young apprentice NAME_2, a succubus-elf hybrid. During an ambush a giant spider manages to bite NAME_1's dick.
When NAME_2 has sucked out the venom, NAME_1 makes her continue sucking him until he fills her mouth with his cum while playing with her tits which he exposed.