Technically, it depends on the impedence / reactance / resistance of the fabric vs the contacts, and the overall voltage involved.

Yeah, a 9 volt battery probably would not be able to make the jump through many kinds of fabrics... but there probably are some very thin fabrics that it could possibly flow through, complete the circuit... such as maybe very low threadcount, loosly knit/woven blends, gossamers of varying kinds... stuff that does generally tend to be more common as negliges or nightgowns or even lingerie... but yeah, still is probably not what I would say is generally common.

Unfortunately I can't easily find a chart with fabric impedence per weave/knit/material composition, so I can't actually do the math on the fly, but the relative electrical conductivity of different fabrics is absolutely a thing in many industrial/mfg contexts lots of research goes into this.

Also... you could just uh... lets not be lewd... you could just use some method to uh, dampen, moisten the contact area of whatever fabric and/or the battery's contacts, and this would significantly lower the impedence of a good deal of common light fabrics.

But yeah, for the most part, there's a reason why contact tasers have their contacts shaped as edged points, and why taser 'pistols' 'shoot' barbs that are intended to puncture through whatever fabric, and go straight into your flesh.