In some of the better language schools in the UK, swearing (the words, definitions, usage and their accompanying gestures) is recognised as a part of the English language and so a whole lesson is usually devoted to it.
Even though it may not be formally stated as being part of the syllabus, any English language teacher, worth his salt, will include it.
The aim is to send the student out equipped with the necessary skills and savvy to help them blend in.
Like with many British English swear words, context and how it is vocalised will alter its meaning.
Bollocks as an expletive is quite mild in potency; and has a mischievous quality about it. I wouldn't use it to swear at someone (it has one syllable too many) or use it to vent anger - I'd use something much stronger (eg fuck).
Observe the conversations between Tom and Harry:
Tom: Yeah, its as light as a feather - kitted out with Dura Ace bits, carbon wheelset...
Harry: Your bike is the dogs [bollocks]!
Tom: That Danny geezer is doing that flip all wrong. He should've pedalled harder up the tree...
Harry: So, you're saying you can do better? You're talking bollocks, mate.
Tom: We won! All six numbers and the bonus number too!
Harry: Bollllllllooooooccccckkkkkkkksssssssss!!!
Tom: We're gonna get a right bollocking for being late again.
Harry: Sorry, mate. I forgot to set the alarm clock last night.
Tom: Straighten up, you just clipped that wing mirror.
Harry: Bollocks!
etc
.
.
.
Other variations of the word bollocks can be used in the same or similar way.
For example:
The mutts nuts = The dogs bollocks
Tom: Yeah, its as light as a feather - kitted out with Dura Ace bits, carbon wheelset...
Harry: Your bike is the mutts nuts!