I've always liked words that sound innocent or that have both innocent and very guilty meanings depending on context. Examples include: sounds (definition, examples) and wands (definition, examples).

The best thing about these words is the in-joke character of them - in other words, to be offended by them, you have to know what they mean, and if you know what they mean, you're probably not going to be offended by them. Example: do a demo/presentation for a prospect. Create a new record of a person in your system. Enter their employer's name as "Acme Stuffed Toy Co." and their profession as "fluffer". See if anyone notices.

For advanced students: if someone does notice, and they're of the appropriate gender, and they giggle - ask them for a date.