1. To convey an expression of awesomeness,epicness or uberness.
2. A spectacular fuck.
3. A lay so epic/uber/awesome/ultimate/super that the orgasm you get is just mother fucking ecstasy.
4. A super fuck that may break your bed
Dude ,she was a great catch but sex with her sister was motherfucking fucktaculous !!!
Usually an interjection, meaning, spectacular! or wonderful!
This is absolutely fucktaculous! I had a fucktaculous time at the party last night!