The best alternative I found to licking was using a damp sponge.
Simply tap the sticky part of the envelope on the wet sponge a few times
and there you go.
Lacking a sponge, anything like a washcloth, towel or paper towel will also work.
lifehacks.stackexchange.com/users/117/Jon
Another alternative is to use a glue stick, I found glue sticks to be very fast and efficient.
A slower option is to use double sided tape as well, but certainly that's not easier than the other options, but if you hate licking it's an option as well.
lifehacks.stackexchange.com/users/155/skv
Buy envelopes with an adhesive band on the seal that's protected by an easy-to-remove film (“peel and seal”), like I do.
Don't they make them in your country?
You can apply ordinary office sticky tape
: it's as fast as licking the rubber band, but it does look uglier.
If you have to use envelopes with a rubber strip serving as do-it-
yourself glue in, you can transfer saliva to your finger then move your finger over the gum on the envelope.
This is significantly slower than licking though.
You can use water instead of saliva, but it doesn't work as well.
Warm water works better than cold water.
If you have many envelopes to seal, keep a sponge or similar material handy.
lifehacks.stackexchange.com/users/1214/Gilles 'SO- stop being evil'
An alternative to the wet sponge is your finger.
Just dip it into a glas of water.
Intuitive and always applicable.
To answer the comment:Paper can cause cuts at it's rigde.
Place the envelope flat on the table and apply the water.
For a cut you won't have the right angle to the ridge.
lifehacks.stackexchange.com/users/172/Stefan Bischof
Use a cool mist humidifier.
I discovered this by accident one day.
Stuffy nose & allergies
so I brought a humidifier to work.
Just run the glue part of the envelope back & forth across the steam spout & it works like a charm.
I'm only made because it took me 30 years of working in an office to figure this one out!lol.
lifehacks.stackexchange.com/users/17835/user17835
Modify a stamp sponge.
Elevate the sponge by putting a crown cork below it.
lifehacks.stackexchange.com/users/172/Stefan Bischof
To expand on the "wet sponge / cloth / finger concept": As we are dealing with multiple envelopes, I recommend layering the flaps of the envelopes, slightly staggered, so that the sticky parts of the flap form a coherent area, looking somewhat like '>>>>'.
Then use your preferred method of moistening (I recommend a damp sponge) to wet all the seals in one go and close one envelope after another.
Instead of folding down each flap, I recommend you grab the envelope at the rectangular part, pull it away from the rest of the sticky pile and fold it up towards the flap, so that the front of the envelope is on top again.
It's one smooth movement without the risk of paper cuts (edge of the flap!)
or sticky fingers.
(Source: Helping with business mass mailings as kid.)
lifehacks.stackexchange.com/users/12132/Stephie
Get a selotape dispenser, the large ones you have in an office.
Without a roll of tape on the reel bit, pour some water into the 'res' where the tape would normally sit, then spin the wheel to get it wet and use this to dampen the envelope.
We used to use this in a post room at a university when doing mass mailings and it works really well, as long as the selotape dispenser has the right kind of 'wheel' on it.
lifehacks.stackexchange.com/users/1558/djsmiley2kStaysInside
Two words : Glue stick.
It will activate the glue already on the flap.
No mess, no paper cuts.
lifehacks.stackexchange.com/users/20369/Brendoodle
I'm sending out Christmas cards and I have to seal about 100 envelopes. However, I can't stand the taste of the part of the envelope meant to be licked. Last year I used tape to seal each envelope but that took too long.   Is there any easy way I can seal the envelopes quickly without licking it?
How to seal envelopes without licking
lifehacks.stackexchange.com
<stationery><office-supplies><adhesive>
lifehacks.stackexchange.com/questions/1862
lifehacks.stackexchange.com/users/20/michaelpri
An effective way to seal an envelope without licking it is to use a damp sponge or a wet finger. Another good method could be to use a glue stick or a cool mist humidifier. Finally, you could consider buying envelopes that already have an adhesive band on the seal. The options include using a damp sponge, a glue stick, double sided tape, 'peel and 'seal' envelopes, a wet finger, a cool mist dehumidifier, a modified stamp sponge or a selotape dispenser.
Use a damp sponge. Use a glue stick or double sided tape. Buy peel and seal envelopes. Dip your finger in a glass of water and run the wet finger over the glue. Run the glue strip over the spout of a cool mist humidifier to moisten. Use a modified stamp sponge elevated by placing a crown cork beneath it. Before moistening lay all the open envelopes on top of each other slightly staggered so that they can be done all in one movement. Use a selotapte dispenser.