Is it possible to experience powerful sensations, such as orgasm, without getting attached to it? I used orgasm as an example because it is usually the strongest sensation one can feel due to everything involved and all the chemistry released in the body.

Also, I would say that sexual activity and drinking are probably the two biggest challenges one has to overcome when following the 8 precepts for weeks or months.

So, can one feel it without attachments?!
Ostensibly, yes, I can't imagine why it wouldn't be technically possible for the body to trigger an orgasm without any kind of mental attachment. Of course, it may be that there is some necessary mental trigger involved, but I doubt that is true. 

In the vinaya there are several cases that seem to suggest involuntary (physical) sexual arousal involving heat and motion; it seems reasonable to suggest that certain conditions could result in an involuntary ejaculation. 

Simpler would be the case where one was intending to bring about an orgasm but then suddenly became mindful, only to find that it was too late (the point being that any attachment created would be in relation to the prior stimulation, not the orgasm itself).

Either way, it is important to clarify that intentionally bringing about an orgasm for the purpose of pleasure invariably leads to the cultivation of attachment.

Incidentally, IIRC, this is one of the issues that led to a split in the sangha, though I can't remember which one. One group thought that the fact that arahants can still experience orgasms meant that they were still not free from defilements; the other claimed that the orgasms were just physical processes with no mental counterpart.