What does "be buggered sideways" mean? [closed]

Americans rarely use bugger anyway, so OP's cited example is very definitely a British slang usage. But the BrE "standard" exclamation is Fuck me sideways! (2,270 hits in Google Books) rather than Bugger me sideways! (441 hits).

But both versions involving "sideways" are normally used to express surprise, rather than to convey the negativity of some outcome or condition. It's also worth noting 270 written instances of Fuck me sideways with XXXX, where XXXX is some almost randomly chosen object such as a rusty poker, my uncle's marrow, a chainsaw, a wooden stake (that's just the first four nouns after with in my search; they're all extreme examples of things you certainly wouldn't want used as a "dildo" in penetrative sex, regardless of the orientation or orifice! :). You might think extensions like that emphasise the surprise, but in practice I'd say their main purpose is to inject a note of levity (and reassurance that the unexpected situation isn't necessarily being perceived as a bad thing).

Regardless of whether the intention is to convey surprise or negativity, most speakers recognise the fuck versions as (potentially, at least) more offensive than those based on bugger. I therefore suspect that quirky extensions such as ... sideways with a red-hot poker occur more often with fuck, simply because they distract attention from the taboo word itself (tending to amplifying the substance of the assertion by focusing on whimsy rather than profanity).

In short, I think sideways in OP's example is a relatively uncommon "flourish" for the context. Personally, I'd usually use the more highly-charged fucked, but if I wanted to distract attention from that I might add something like If it does, we'll all be fucked six ways from Sunday (that's 190 hits in Google Books).