Need some advice and/or ideas

This can be a difficult one to break. Many have associated masturbation and onset of sleep together. As the famous saying goes, when neurons fire together they wire together. If this has been your habit for long period of time, this can be challenging. I sometimes struggle with this as well. Here are some suggestions:
1. Only go to bed when you are very tired
2. If you can't sleep, get out of bed and do something else. Avoid anything that may arouse you.
3. Optimize your sleeping environment. No screens, no light, make sure the ambient temperature is slightly cold.
4. Try taking a warm bath before going to sleep.
5. gratitude journal before going to bed, review your goals and life creed

Hope this helps. Good luck. You may have some restless nights at first. It will only get easier as you progress further. Anything good in life requires effort. Stay strong.

 

What @taqwa said, as an optional twist: I have periods where I jump on the treadmill, take a cold shower and then go to bed.
In the end sleeping shorter and deeper is solves this problem and boosts your day way more than sleeping longer and lighter

 

Even I have this issue.
Habit of jerking before sleeping.
Every night my junk expects me to do it, keeps getting hard.

The way out is to tire yourself during the day, work and exercise.
Cold shower
Just try to clear mind when you go to bed.
I immediately grab 2 pillows and hug them to sleep so that my hands don't wander.