What could you wear under your new swimming jammers to prevent your member from being seen and would do need to?

Lol this question makes me laugh! If you are talking about a swim meet, absolutely DO NOT wear anything under you jammers as it will create unnecessary drag. If this is not your biggest meet of the season and you are 100% NOT tapered for it, that would be a question to bring up with your coach!

If this is just practice you're talking about, most male swimmers will either wear speedos and a drag suit or jammers with a drag suit. Drag suits are the mesh short type things. Sorry I don't have a better description of them!