The question “Do you prefer sex or fucking in Spanish?” can be translated in several ways, with the appropriate choice depending heavily on the desired tone and the specific Spanish-speaking region

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“Sex”

The most direct and universally understood way to refer to “sex” is:

• el sexo (the sex) 

To ask the general question “Do you prefer sex or fucking?” you could phrase it neutrally as:

• ¿Prefieres el sexo o follar? (Do you prefer sex or to fuck?) 

“Fucking”

The word “fucking” is much more colloquial and its translation varies drastically by region. You must be aware of local slang to avoid misunderstandings. 

• Follar: Very common in Spain.
• Coger: The most common and neutral word for “to have sex” in many Latin American countries, but it is considered a very strong vulgarity in others (especially Argentina/Mexico).
• Tirar: Widely used in many places (Venezuela, Mexico, etc.).
• Culear: Common in Ecuador, Panama, Venezuela, etc., but also highly vulgar.
• Chingar: A strong and vulgar word, especially prevalent in Mexico, where it has many variations. 

Example Phrases

Here are some ways to ask the second part of your question, “or fucking?”, using regional variations:

• ¿… o echar un polvo/palo? (Spain/Venezuela – “or have a quickie?”)
• ¿… o coger? (Most of Latin America)
• ¿… o chingar? (Mexico) 

It is important to remember that these terms are slang and their appropriateness depends entirely on the context and the people you are speaking with. For a comprehensive dictionary with regional tags, consult resources like SpanishDictionary.com or forums like the r/Spanish subreddit for specific local nuances.