Help Initiating Sexting -- Reserved Husband

My husband is very reserved when it comes to sex. We were both virgins when we got married and neither has ever been with anyone else. For a long time (years) he was extremely sexually repressed but slowly over time I've gotten him to open up and the sex has gotten MILES better. But I still feel like I want more; I still feel like we're both holding back. After six years of marriage, sex is still nerve-wracking and intimidating (and frequently rote) so my goal is for it to be more casual/natural. One thing I'd like for us to get more natural at is sexting. We've done it a few times but I always initiate and I feel like it's a lot of work. Sometimes it works out but most of the time I'm left disappointed because it doesn't go how I wanted....I'm ok with that because I know that every time you try something new its trial-and-error at first, you can't expect things to be perfect. But past failure definitely makes me feel paralyzed.

In the past, the thing that worked the best was sending photos...but when I do that I feel like I've skipped all the foreplay and it's over too quickly. (Plus, if he's not available to flirt back then I've wasted a bunch of time trying to take the perfect photo for him). Id like for us to learn to sext using only words. I know that if (and when) we get started I'll be fine but what scares me is just making the first move. I need ideas on how to start the conversation. How do you ladies initiate? What are your first couple lines to get things rolling? I'd like specific examples.

I'd like to say something that is teasing but still blatant enough that he knows what I'm getting at (his mind won't go there unless I point him in that direction). He gets nervous easy so if anyone had ideas about making him feel less awkward, that'd be great. Most likely I'd need to lead for most of the conversation.