I have used similar method sometimes when i need to tack weld to large gaps. But i have removed the covering from the other rod, and feed some extra material from it to the weld with my other hand. Works specially vertical positions. Quality of that kind of weld ain't good, so those tacks needs to be removed during welding.

Method you used has couple issues that needs to be notified.
If you weld too thick weld to the groove with one run, it can easily crack.

Slack can easily get under the weld.

Weld is too hot, it makes under cuts to the sides, it may harden...

Welding is one of those things, where you can't use shortcuts.
If you want good quality. Sorry.