I love fluid threads, be it precum, semen, vaginal discharge or saliva. Rarely, I have even experienced anal mucous thread when having extended anal sex. For me, sex has always centered around the exchange of body fluids through penetration. Knowing you're consuming someone's body fluid as they consume yours, is nirvana.
Chroniques sexuelles d’une famille d’aujourd’hui" that’s the name of the film , it’s on here somewhere, this is the only scene with him , worth a watch it’s a great film