How do silicone earplugs work?

[Knitjob]

I'm doing a triathlon at the weekend and I've had a cold all week and my ears hurt. So I bought some silicone earplugs for swimming. But I haven't a clue how they work. Not a clue. How do they stay in? Has anyone used them? I can manage to get them to stay in while I walk around the house keeping my head quite still but will they honestly stay in while I swim? I'm going for a swim this afternoon to try them out.

Sorry this is probably a bit late but here goes: silicone earplugs need to be warmed and moulded and rolled into a ball between your palms and then applied with gentle pressure over the opening to the ear canal. Proper earplugs will have instructions on them. You mustn't shove them down your ear canal as you won't get them out! There's a video here.