Could rubbing cause erectile dysfunction?

hi there

Since i have started mastrubating i have been a fan of the humping my bed method but i want to get out of that habit coz i think its causing me erectile disfunction coz my erections are not as hard as they have been.

So i dont use lubrication or nething is there ne other methods i can try that dont include ne objects or nething..

Plus how does one whos never fingered him self do it im curious to try it as ive read about it on other sites.,.