Thank you for your question about pruning back your juniper plants.  This is a classic situation of right plant---wrong spot.  Unfortunately, the junipers will keep growing larger in the coming years.  However, they do respond well to pruning.  Junipers are best pruned when the plant is pushing new growth in spring.  They are among the conifers that do not form new buds on old growth, so avoid cutting back to brown older stems.  (This is called the dead zone, and is an area where new growth cannot occur.  If you prune into it you will have unsightly dead-looking areas in your shrubs.)  Prune only on new growth, snipping the branch tips, unless entire branches will be removed to the base.  To head the plants back, you can make cuts back toward the center of the plants, making each cut just beyond a new branch or at the trunk.

Here's an article from Michigan State University that gives some good juniper pruning tips:
https://www.canr.msu.edu/news/pruning_evergreen_shrubs

To keep your plants in bounds you will need to do this pruning each year.  As the Michigan State University article notes, when you cut branches at their point of origin, either on the stem or trunk, less new growth will be stimulated, which is what you want.

Best of luck with your juniper thicket.