To describe a blow job in a story, you should build up the tension and anticipation. Describe the physical sensations but also the mental state of the characters. Make it sensual without crossing into the realm of pornography.
In general, such stories are considered inappropriate for mainstream literature due to their vulgar nature. Literature often aims to convey more positive, moral, and universal values. However, in some forms of adult - oriented or niche writing, they might exist but are not widely accepted in the broader literary community.
Well, it's really not okay. These kinds of stories involve private and sexual matters. In a civilized society, we should respect others and not spread such private sexual content in public. It's not only a matter of propriety but also related to moral and ethical values.
One common 'blow job horror story' in movies could be when a character is forced into an unwanted situation. For example, in some crime thrillers, a victim might be coerced into performing such an act against their will. It's used to show the brutality and power dynamics in a really dark and disturbing way.