No need to get touchy, chionos, your ignorance can be quickly fixed.

"smurfing massive bag" - a bag that is smurfing massive.
"Pretty massive smurfing bag" - Quite a large bag. Swear word is just a swear word rather than an adjective. Similar to "massive smurf-off bag". E.g. "I just took a massive smurfing dump, now the bathroom's smurfing swamped." Same word, different meanings. You just need to read it in the right cadence instead of being an idiot. Although it may just be that you're not English and suffer from a lack of ridiculously creative language. I'm not sure if many places use terms like "adjective smurf-off noun".

Now let's go back to wanking Paul off before you embarrass yourself.