I don’t know why it took me so many years to understand that If I don’t write down my song ideas (riffs, melodies etc.) ASAP those ideas are gone forever. My advice is that tour notebook / phone is your best friend when collecting ideas for songs.
Here’s one riff I was able to collect with me few years back. Send me a message if you’d like to use it in your songs / beats etc. so I can send you the stem in better quality and performance.